Add adaptive media variants for weak networks

2026-05-19 18:33:42 +03:00
--- a/src/common/utils/public-url.util.spec.ts
+++ b/src/common/utils/public-url.util.spec.ts
@@ -1,4 +1,9 @@
-import { resolveManagedFileUrl, resolveManagedFileUrls } from './public-url.util';
+import {
+  resolveManagedFileUrl,
+  resolveManagedFileUrlRecord,
+  resolveManagedFileUrlRecords,
+  resolveManagedFileUrls,
+} from './public-url.util';

 describe('public url util', () => {
  const originalPublicBaseUrl = process.env.PUBLIC_BASE_URL;
@@ -26,4 +31,34 @@ describe('public url util', () => {
      'http://192.168.1.12:4000/uploads/b.png',
    ]);
  });
+
+  it('resolves url objects used for media variants', () => {
+    expect(
+      resolveManagedFileUrlRecord({
+        lowUrl: '/uploads/posts/images/image-1/low.webp',
+        mediumUrl: '/uploads/posts/images/image-1/medium.webp',
+        externalUrl: 'https://cdn.example.com/image.webp',
+      }),
+    ).toEqual({
+      lowUrl: 'http://192.168.1.12:4000/uploads/posts/images/image-1/low.webp',
+      mediumUrl: 'http://192.168.1.12:4000/uploads/posts/images/image-1/medium.webp',
+      externalUrl: 'https://cdn.example.com/image.webp',
+    });
+  });
+
+  it('resolves arrays of media variant objects', () => {
+    expect(
+      resolveManagedFileUrlRecords([
+        {
+          lowUrl: '/uploads/posts/images/image-1/low.webp',
+          mediumUrl: '/uploads/posts/images/image-1/medium.webp',
+        },
+      ]),
+    ).toEqual([
+      {
+        lowUrl: 'http://192.168.1.12:4000/uploads/posts/images/image-1/low.webp',
+        mediumUrl: 'http://192.168.1.12:4000/uploads/posts/images/image-1/medium.webp',
+      },
+    ]);
+  });
 });
--- a/src/common/utils/public-url.util.ts
+++ b/src/common/utils/public-url.util.ts
@@ -25,3 +25,21 @@ export const resolveManagedFileUrls = (fileUrls: unknown): unknown => {

  return fileUrls.map((fileUrl) => resolveManagedFileUrl(fileUrl));
 };
+
+export const resolveManagedFileUrlRecord = (value: unknown): unknown => {
+  if (!value || typeof value !== 'object' || Array.isArray(value)) {
+    return value;
+  }
+
+  return Object.fromEntries(
+    Object.entries(value).map(([key, entryValue]) => [key, resolveManagedFileUrl(entryValue)]),
+  );
+};
+
+export const resolveManagedFileUrlRecords = (value: unknown): unknown => {
+  if (!Array.isArray(value)) {
+    return value;
+  }
+
+  return value.map((entry) => resolveManagedFileUrlRecord(entry));
+};
--- a/src/config/configuration.ts
+++ b/src/config/configuration.ts
@@ -94,9 +94,24 @@ export default () => ({
        (process.env.S3_FORCE_PATH_STYLE ?? 'false').toLowerCase() === 'true',
    },
  },
+  imageProcessing: {
+    enabled:
+      typeof process.env.IMAGE_PROCESSING_ENABLED === 'string'
+        ? process.env.IMAGE_PROCESSING_ENABLED.toLowerCase() === 'true'
+        : (process.env.VIDEO_PROCESSING_ENABLED ?? 'false').toLowerCase() === 'true',
+    ffmpegPath:
+      process.env.IMAGE_PROCESSING_FFMPEG_PATH ??
+      process.env.VIDEO_PROCESSING_FFMPEG_PATH ??
+      'ffmpeg',
+    lowWidth: Number(process.env.IMAGE_PROCESSING_LOW_WIDTH ?? 360),
+    mediumWidth: Number(process.env.IMAGE_PROCESSING_MEDIUM_WIDTH ?? 720),
+    highWidth: Number(process.env.IMAGE_PROCESSING_HIGH_WIDTH ?? 1280),
+    quality: Number(process.env.IMAGE_PROCESSING_QUALITY ?? 78),
+  },
  videoProcessing: {
    enabled: (process.env.VIDEO_PROCESSING_ENABLED ?? 'false').toLowerCase() === 'true',
    ffmpegPath: process.env.VIDEO_PROCESSING_FFMPEG_PATH ?? 'ffmpeg',
+    ffprobePath: process.env.VIDEO_PROCESSING_FFPROBE_PATH ?? '',
    maxWidth: Number(process.env.VIDEO_PROCESSING_MAX_WIDTH ?? 1280),
    maxFps: Number(process.env.VIDEO_PROCESSING_MAX_FPS ?? 30),
    crf: Number(process.env.VIDEO_PROCESSING_CRF ?? 28),
--- a/src/config/validation.schema.ts
+++ b/src/config/validation.schema.ts
@@ -61,8 +61,15 @@ export const validationSchema = Joi.object({
  S3_ACCESS_KEY_ID: Joi.string().allow('').optional(),
  S3_SECRET_ACCESS_KEY: Joi.string().allow('').optional(),
  S3_FORCE_PATH_STYLE: Joi.boolean().truthy('true').falsy('false').default(false),
+  IMAGE_PROCESSING_ENABLED: Joi.boolean().truthy('true').falsy('false').optional(),
+  IMAGE_PROCESSING_FFMPEG_PATH: Joi.string().allow('').optional(),
+  IMAGE_PROCESSING_LOW_WIDTH: Joi.number().min(160).max(1920).default(360),
+  IMAGE_PROCESSING_MEDIUM_WIDTH: Joi.number().min(160).max(2560).default(720),
+  IMAGE_PROCESSING_HIGH_WIDTH: Joi.number().min(320).max(3840).default(1280),
+  IMAGE_PROCESSING_QUALITY: Joi.number().min(40).max(100).default(78),
  VIDEO_PROCESSING_ENABLED: Joi.boolean().truthy('true').falsy('false').default(false),
  VIDEO_PROCESSING_FFMPEG_PATH: Joi.string().default('ffmpeg'),
+  VIDEO_PROCESSING_FFPROBE_PATH: Joi.string().allow('').optional(),
  VIDEO_PROCESSING_MAX_WIDTH: Joi.number().min(320).max(3840).default(1280),
  VIDEO_PROCESSING_MAX_FPS: Joi.number().min(12).max(60).default(30),
  VIDEO_PROCESSING_CRF: Joi.number().min(18).max(35).default(28),
--- a/src/infrastructure/storage/image-processing.service.ts
+++ b/src/infrastructure/storage/image-processing.service.ts
@@ -0,0 +1,245 @@
+import { Injectable, Logger } from '@nestjs/common';
+import { ConfigService } from '@nestjs/config';
+import { spawn } from 'child_process';
+import { mkdtemp, readFile, rm, writeFile } from 'fs/promises';
+import { tmpdir } from 'os';
+import { extname, join } from 'path';
+
+export type UploadedImageFile = {
+  mimetype?: string;
+  size: number;
+  buffer: Buffer;
+  originalname?: string;
+};
+
+export type ProcessedImageVariantName = 'original' | 'low' | 'medium' | 'high';
+
+export type ProcessedImageResult = {
+  primaryVariantName: ProcessedImageVariantName;
+  variants: Array<{
+    name: ProcessedImageVariantName;
+    relativePath: string;
+    extension: string;
+    buffer: Buffer;
+    contentType: string;
+  }>;
+};
+
+@Injectable()
+export class ImageProcessingService {
+  private readonly logger = new Logger(ImageProcessingService.name);
+  private ffmpegAvailabilityResolved = false;
+  private ffmpegAvailable = false;
+
+  constructor(private readonly configService: ConfigService) {}
+
+  async processForResponsiveDelivery(file: UploadedImageFile): Promise<ProcessedImageResult> {
+    const originalVariant: ProcessedImageResult['variants'][number] = {
+      name: 'original',
+      relativePath: `original${this.resolveInputExtension(file)}`,
+      extension: this.resolveInputExtension(file),
+      buffer: file.buffer,
+      contentType: this.resolveOriginalContentType(file),
+    };
+
+    if (!this.isEnabled()) {
+      return {
+        primaryVariantName: 'original',
+        variants: [originalVariant],
+      };
+    }
+
+    const ffmpegReady = await this.ensureFfmpegAvailable();
+    if (!ffmpegReady) {
+      return {
+        primaryVariantName: 'original',
+        variants: [originalVariant],
+      };
+    }
+
+    const workingDir = await mkdtemp(join(tmpdir(), 'oudelaa-image-'));
+    const inputPath = join(workingDir, `input${this.resolveInputExtension(file)}`);
+
+    try {
+      await writeFile(inputPath, file.buffer);
+
+      const lowVariant = await this.generateWebpVariant(inputPath, workingDir, 'low', this.getLowWidth());
+      const mediumVariant = await this.generateWebpVariant(
+        inputPath,
+        workingDir,
+        'medium',
+        this.getMediumWidth(),
+      );
+      const highVariant = await this.generateWebpVariant(inputPath, workingDir, 'high', this.getHighWidth());
+
+      return {
+        primaryVariantName: 'medium',
+        variants: [originalVariant, lowVariant, mediumVariant, highVariant],
+      };
+    } catch (error) {
+      this.logger.warn(
+        `Image optimization failed for "${file.originalname ?? 'upload'}": ${
+          error instanceof Error ? error.message : 'unknown error'
+        }`,
+      );
+
+      return {
+        primaryVariantName: 'original',
+        variants: [originalVariant],
+      };
+    } finally {
+      await rm(workingDir, { recursive: true, force: true });
+    }
+  }
+
+  private isEnabled(): boolean {
+    const explicit = this.configService.get<boolean>('imageProcessing.enabled', { infer: true });
+    if (typeof explicit === 'boolean') {
+      return explicit;
+    }
+
+    return this.configService.get<boolean>('videoProcessing.enabled', { infer: true }) ?? false;
+  }
+
+  private getFfmpegPath(): string {
+    return (
+      this.configService.get<string>('imageProcessing.ffmpegPath', { infer: true }) ??
+      this.configService.get<string>('videoProcessing.ffmpegPath', { infer: true }) ??
+      'ffmpeg'
+    ).trim();
+  }
+
+  private getLowWidth(): number {
+    return this.configService.get<number>('imageProcessing.lowWidth', { infer: true }) ?? 360;
+  }
+
+  private getMediumWidth(): number {
+    return this.configService.get<number>('imageProcessing.mediumWidth', { infer: true }) ?? 720;
+  }
+
+  private getHighWidth(): number {
+    return this.configService.get<number>('imageProcessing.highWidth', { infer: true }) ?? 1280;
+  }
+
+  private getQuality(): number {
+    return this.configService.get<number>('imageProcessing.quality', { infer: true }) ?? 78;
+  }
+
+  private resolveInputExtension(file: UploadedImageFile): string {
+    const extension = extname(file.originalname ?? '').toLowerCase();
+    if (extension) {
+      return extension;
+    }
+
+    switch (file.mimetype) {
+      case 'image/jpeg':
+        return '.jpg';
+      case 'image/png':
+        return '.png';
+      case 'image/webp':
+        return '.webp';
+      case 'image/gif':
+        return '.gif';
+      default:
+        return '.jpg';
+    }
+  }
+
+  private resolveOriginalContentType(file: UploadedImageFile): string {
+    if (file.mimetype?.trim()) {
+      return file.mimetype;
+    }
+
+    switch (this.resolveInputExtension(file)) {
+      case '.png':
+        return 'image/png';
+      case '.webp':
+        return 'image/webp';
+      case '.gif':
+        return 'image/gif';
+      case '.jpg':
+      case '.jpeg':
+      default:
+        return 'image/jpeg';
+    }
+  }
+
+  private async generateWebpVariant(
+    inputPath: string,
+    workingDir: string,
+    name: Exclude<ProcessedImageVariantName, 'original'>,
+    width: number,
+  ): Promise<ProcessedImageResult['variants'][number]> {
+    const outputPath = join(workingDir, `${name}.webp`);
+
+    await this.runFfmpeg([
+      '-y',
+      '-i',
+      inputPath,
+      '-frames:v',
+      '1',
+      '-vf',
+      `scale='min(${width},iw)':-2:force_original_aspect_ratio=decrease`,
+      '-c:v',
+      'libwebp',
+      '-compression_level',
+      '6',
+      '-q:v',
+      String(this.getQuality()),
+      outputPath,
+    ]);
+
+    return {
+      name,
+      relativePath: `${name}.webp`,
+      extension: '.webp',
+      buffer: await readFile(outputPath),
+      contentType: 'image/webp',
+    };
+  }
+
+  private async ensureFfmpegAvailable(): Promise<boolean> {
+    if (this.ffmpegAvailabilityResolved) {
+      return this.ffmpegAvailable;
+    }
+
+    try {
+      await this.runFfmpeg(['-version']);
+      this.ffmpegAvailable = true;
+    } catch (error) {
+      this.ffmpegAvailable = false;
+      this.logger.warn(
+        `Image processing is enabled, but ffmpeg is unavailable at "${this.getFfmpegPath()}": ${
+          error instanceof Error ? error.message : 'unknown error'
+        }`,
+      );
+    }
+
+    this.ffmpegAvailabilityResolved = true;
+    return this.ffmpegAvailable;
+  }
+
+  private async runFfmpeg(args: string[]): Promise<void> {
+    await new Promise<void>((resolve, reject) => {
+      const child = spawn(this.getFfmpegPath(), args, { windowsHide: true });
+      let stderr = '';
+
+      child.stderr.on('data', (chunk) => {
+        stderr += chunk.toString();
+      });
+
+      child.on('error', (error) => {
+        reject(error);
+      });
+
+      child.on('close', (code) => {
+        if (code === 0) {
+          resolve();
+          return;
+        }
+
+        reject(new Error(stderr.trim() || `ffmpeg exited with code ${code ?? 'unknown'}`));
+      });
+    });
+  }
+}
--- a/src/infrastructure/storage/storage.module.ts
+++ b/src/infrastructure/storage/storage.module.ts
@@ -1,10 +1,11 @@
 import { Global, Module } from '@nestjs/common';
+import { ImageProcessingService } from './image-processing.service';
 import { ManagedStorageService } from './managed-storage.service';
 import { VideoProcessingService } from './video-processing.service';

@Global()
@Module({
-  providers: [ManagedStorageService, VideoProcessingService],
-  exports: [ManagedStorageService, VideoProcessingService],
+  providers: [ManagedStorageService, VideoProcessingService, ImageProcessingService],
+  exports: [ManagedStorageService, VideoProcessingService, ImageProcessingService],
 })
 export class StorageModule {}
--- a/src/infrastructure/storage/video-processing.service.ts
+++ b/src/infrastructure/storage/video-processing.service.ts
@@ -30,6 +30,19 @@ export type OptimizedVideoResult = {
  };
 };

+type ProbedVideoInfo = {
+  hasAudio: boolean;
+  width: number;
+};
+
+type HlsRendition = {
+  width: number;
+  videoBitrateKbps: number;
+  maxRateKbps: number;
+  bufSizeKbps: number;
+  audioBitrateKbps: number;
+};
+
@Injectable()
 export class VideoProcessingService {
  private readonly logger = new Logger(VideoProcessingService.name);
@@ -180,6 +193,24 @@ export class VideoProcessingService {
    ).trim();
  }

+  private getFfprobePath(): string {
+    const configured = (
+      this.configService.get<string>('videoProcessing.ffprobePath', { infer: true }) ?? ''
+    ).trim();
+    if (configured) {
+      return configured;
+    }
+
+    const ffmpegPath = this.getFfmpegPath();
+    if (/ffmpeg(?:\.exe)?$/i.test(ffmpegPath)) {
+      return ffmpegPath.replace(/ffmpeg(?:\.exe)?$/i, (match) =>
+        match.toLowerCase().endsWith('.exe') ? 'ffprobe.exe' : 'ffprobe',
+      );
+    }
+
+    return 'ffprobe';
+  }
+
  private getMaxWidth(): number {
    return this.configService.get<number>('videoProcessing.maxWidth', { infer: true }) ?? 1280;
  }
@@ -257,6 +288,112 @@ export class VideoProcessingService {
  ): Promise<NonNullable<OptimizedVideoResult['generatedHls']>> {
    await mkdir(hlsDir, { recursive: true });

+    let probe: ProbedVideoInfo | null = null;
+    try {
+      probe = await this.probeVideo(optimizedMp4Path);
+    } catch (error) {
+      this.logger.warn(
+        `Video probe failed before adaptive HLS generation: ${
+          error instanceof Error ? error.message : 'unknown error'
+        }`,
+      );
+    }
+
+    const renditions = this.buildHlsRenditions(probe?.width ?? this.getMaxWidth());
+    if (!probe || renditions.length <= 1) {
+      return this.generateSingleRenditionHlsPackage(optimizedMp4Path, hlsDir);
+    }
+
+    for (let index = 0; index < renditions.length; index += 1) {
+      await mkdir(join(hlsDir, `stream_${index}`), { recursive: true });
+    }
+
+    const args = ['-y', '-i', optimizedMp4Path];
+    args.push('-filter_complex', this.buildAdaptiveHlsFilterComplex(renditions));
+
+    for (let index = 0; index < renditions.length; index += 1) {
+      args.push('-map', `[v${index}out]`);
+      if (probe.hasAudio) {
+        args.push('-map', '0:a:0');
+      }
+    }
+
+    renditions.forEach((rendition, index) => {
+      args.push(
+        `-c:v:${index}`,
+        'libx264',
+        `-b:v:${index}`,
+        `${rendition.videoBitrateKbps}k`,
+        `-maxrate:v:${index}`,
+        `${rendition.maxRateKbps}k`,
+        `-bufsize:v:${index}`,
+        `${rendition.bufSizeKbps}k`,
+        `-g:v:${index}`,
+        String(this.getMaxFps() * 2),
+        `-keyint_min:v:${index}`,
+        String(this.getMaxFps() * 2),
+        `-sc_threshold:v:${index}`,
+        '0',
+        `-preset:v:${index}`,
+        this.getPreset(),
+      );
+
+      if (probe.hasAudio) {
+        args.push(
+          `-c:a:${index}`,
+          'aac',
+          `-b:a:${index}`,
+          `${rendition.audioBitrateKbps}k`,
+          `-ac:a:${index}`,
+          '2',
+          `-ar:a:${index}`,
+          '44100',
+        );
+      }
+    });
+
+    args.push(
+      '-f',
+      'hls',
+      '-hls_time',
+      String(this.getHlsSegmentDurationSeconds()),
+      '-hls_playlist_type',
+      'vod',
+      '-hls_list_size',
+      '0',
+      '-hls_flags',
+      'independent_segments',
+      '-hls_segment_type',
+      'fmp4',
+      '-master_pl_name',
+      'master.m3u8',
+      '-hls_fmp4_init_filename',
+      'stream_%v/init.mp4',
+      '-hls_segment_filename',
+      join(hlsDir, 'stream_%v/segment-%03d.m4s'),
+      '-var_stream_map',
+      probe.hasAudio
+        ? renditions.map((_, index) => `v:${index},a:${index}`).join(' ')
+        : renditions.map((_, index) => `v:${index}`).join(' '),
+      join(hlsDir, 'stream_%v/playlist.m3u8'),
+    );
+
+    await this.runFfmpeg(args);
+
+    const files = await this.readFilesRecursively(hlsDir);
+
+    return {
+      playlistRelativePath: 'master.m3u8',
+      files,
+    };
+  }
+
+  private async generateSingleRenditionHlsPackage(
+    optimizedMp4Path: string,
+    hlsDir: string,
+  ): Promise<NonNullable<OptimizedVideoResult['generatedHls']>> {
+    await mkdir(hlsDir, { recursive: true });
+
    await this.runFfmpeg([
      '-y',
      '-i',
@@ -288,14 +425,7 @@ export class VideoProcessingService {
      join(hlsDir, 'playlist.m3u8'),
    ]);

-    const fileNames = (await readdir(hlsDir)).sort((left, right) => left.localeCompare(right));
-    const files = await Promise.all(
-      fileNames.map(async (fileName) => ({
-        relativePath: fileName,
-        buffer: await readFile(join(hlsDir, fileName)),
-        contentType: this.resolveStreamingContentType(fileName),
-      })),
-    );
+    const files = await this.readFilesRecursively(hlsDir);

    return {
      playlistRelativePath: 'playlist.m3u8',
@@ -303,6 +433,119 @@ export class VideoProcessingService {
    };
  }

+  private buildAdaptiveHlsFilterComplex(renditions: HlsRendition[]): string {
+    if (renditions.length === 1) {
+      return `[0:v]${this.buildAdaptiveScaleFilter(renditions[0].width)}[v0out]`;
+    }
+
+    const splitOutputs = renditions.map((_, index) => `[v${index}]`).join('');
+    const split = `[0:v]split=${renditions.length}${splitOutputs}`;
+    const transforms = renditions.map(
+      (rendition, index) =>
+        `[v${index}]${this.buildAdaptiveScaleFilter(rendition.width)}[v${index}out]`,
+    );
+
+    return [split, ...transforms].join(';');
+  }
+
+  private buildAdaptiveScaleFilter(width: number): string {
+    return `scale='min(${width},iw)':-2:force_original_aspect_ratio=decrease,fps=${this.getMaxFps()},format=yuv420p`;
+  }
+
+  private buildHlsRenditions(sourceWidth: number): HlsRendition[] {
+    const requestedWidths = [Math.min(480, this.getMaxWidth()), Math.min(720, this.getMaxWidth()), this.getMaxWidth()];
+    const widths = Array.from(
+      new Set(
+        requestedWidths
+          .map((width) => Math.max(240, Math.min(width, sourceWidth)))
+          .filter((width) => Number.isFinite(width)),
+      ),
+    ).sort((left, right) => left - right);
+
+    return widths.map((width) => this.resolveHlsRendition(width));
+  }
+
+  private resolveHlsRendition(width: number): HlsRendition {
+    if (width <= 480) {
+      return {
+        width,
+        videoBitrateKbps: 800,
+        maxRateKbps: 960,
+        bufSizeKbps: 1600,
+        audioBitrateKbps: 96,
+      };
+    }
+
+    if (width <= 720) {
+      return {
+        width,
+        videoBitrateKbps: 1600,
+        maxRateKbps: 1920,
+        bufSizeKbps: 3200,
+        audioBitrateKbps: 128,
+      };
+    }
+
+    return {
+      width,
+      videoBitrateKbps: 2800,
+      maxRateKbps: 3360,
+      bufSizeKbps: 5600,
+      audioBitrateKbps: 128,
+    };
+  }
+
+  private async probeVideo(inputPath: string): Promise<ProbedVideoInfo> {
+    const stdout = await this.runCommand(this.getFfprobePath(), [
+      '-v',
+      'error',
+      '-show_entries',
+      'stream=codec_type,width',
+      '-of',
+      'json',
+      inputPath,
+    ]);
+
+    const parsed = JSON.parse(stdout) as {
+      streams?: Array<{ codec_type?: string; width?: number }>;
+    };
+    const streams = parsed.streams ?? [];
+    const videoStream = streams.find((stream) => stream.codec_type === 'video');
+    if (!videoStream?.width) {
+      throw new Error('ffprobe did not return a video width');
+    }
+
+    return {
+      width: videoStream.width,
+      hasAudio: streams.some((stream) => stream.codec_type === 'audio'),
+    };
+  }
+
+  private async readFilesRecursively(
+    baseDir: string,
+    currentDir = baseDir,
+  ): Promise<Array<{ relativePath: string; buffer: Buffer; contentType: string }>> {
+    const entries = await readdir(currentDir, { withFileTypes: true });
+    const files: Array<{ relativePath: string; buffer: Buffer; contentType: string }> = [];
+
+    for (const entry of entries.sort((left, right) => left.name.localeCompare(right.name))) {
+      const absolutePath = join(currentDir, entry.name);
+      if (entry.isDirectory()) {
+        files.push(...(await this.readFilesRecursively(baseDir, absolutePath)));
+        continue;
+      }
+
+      const relativePath = absolutePath.slice(baseDir.length + 1).replace(/\\/g, '/');
+      files.push({
+        relativePath,
+        buffer: await readFile(absolutePath),
+        contentType: this.resolveStreamingContentType(relativePath),
+      });
+    }
+
+    return files;
+  }
+
  private resolveStreamingContentType(fileName: string): string {
    const extension = extname(fileName).toLowerCase();

@@ -341,11 +584,16 @@ export class VideoProcessingService {
    return this.ffmpegAvailable;
  }

-  private async runFfmpeg(args: string[]): Promise<void> {
-    await new Promise<void>((resolve, reject) => {
-      const child = spawn(this.getFfmpegPath(), args, { windowsHide: true });
+  private async runCommand(command: string, args: string[]): Promise<string> {
+    return new Promise<string>((resolve, reject) => {
+      const child = spawn(command, args, { windowsHide: true });
+      let stdout = '';
      let stderr = '';

+      child.stdout.on('data', (chunk) => {
+        stdout += chunk.toString();
+      });
+
      child.stderr.on('data', (chunk) => {
        stderr += chunk.toString();
      });
@@ -356,12 +604,16 @@ export class VideoProcessingService {

      child.on('close', (code) => {
        if (code === 0) {
-          resolve();
+          resolve(stdout);
          return;
        }

-        reject(new Error(stderr.trim() || `ffmpeg exited with code ${code ?? 'unknown'}`));
+        reject(new Error(stderr.trim() || `${command} exited with code ${code ?? 'unknown'}`));
      });
    });
  }
+
+  private async runFfmpeg(args: string[]): Promise<void> {
+    await this.runCommand(this.getFfmpegPath(), args);
+  }
 }
--- a/src/modules/posts/posts.service.ts
+++ b/src/modules/posts/posts.service.ts
@@ -12,6 +12,10 @@ import {
  normalizeWaveformPeaks,
 } from '../../common/utils/waveform.util';
 import { FeedVersionService } from '../../infrastructure/cache/feed-version.service';
+import {
+  ImageProcessingService,
+  UploadedImageFile,
+} from '../../infrastructure/storage/image-processing.service';
 import { ManagedStorageService } from '../../infrastructure/storage/managed-storage.service';
 import {
  UploadedVideoFile,
@@ -26,7 +30,7 @@ import { CreatePostDto } from './dto/create-post.dto';
 import { PostQueryDto } from './dto/post-query.dto';
 import { ReelQueryDto } from './dto/reel-query.dto';
 import { UpdatePostDto } from './dto/update-post.dto';
-import { PostDocument } from './schemas/post.schema';
+import { PostDocument, PostMediaVariantSet } from './schemas/post.schema';
 import { PostsRepository } from './posts.repository';

 type PostMediaMetadataInput = Pick<
@@ -52,6 +56,12 @@ type SavedVideoUpload = {
  videoUrl: string;
  hlsUrl: string;
  thumbnailUrl: string;
+  thumbnailVariants: PostMediaVariantSet | null;
+};
+
+type SavedImageUpload = {
+  primaryUrl: string;
+  variants: PostMediaVariantSet;
 };

@Injectable()
@@ -62,6 +72,7 @@ export class PostsService {
    private readonly postsRepository: PostsRepository,
    private readonly usersRepository: UsersRepository,
    private readonly storageService: ManagedStorageService,
+    private readonly imageProcessingService: ImageProcessingService,
    private readonly videoProcessingService: VideoProcessingService,
    private readonly feedVersionService: FeedVersionService,
    private readonly notificationsService: NotificationsService,
@@ -98,13 +109,17 @@ export class PostsService {
      throw new BadRequestException('Post can contain either images or audio, not both');
    }

-    const uploadedImageUrls = await this.saveImageFiles(imageFiles);
+    const savedImageUploads = await this.saveImageFiles(imageFiles);
+    const uploadedImageUrls = savedImageUploads.map((item) => item.primaryUrl);
+    const uploadedImageVariants = savedImageUploads.map((item) => item.variants);
    const savedVideoUpload = videoFile ? await this.saveVideoUpload(videoFile) : null;
    const uploadedVideoUrl = savedVideoUpload?.videoUrl ?? '';
    const uploadedHlsUrl = savedVideoUpload?.hlsUrl ?? '';
    const uploadedThumbnailUrl = savedVideoUpload?.thumbnailUrl ?? '';
+    const uploadedThumbnailVariants = savedVideoUpload?.thumbnailVariants ?? null;
    const uploadedAudioUrl = audioFile ? await this.saveMediaFile('audio', audioFile) : '';
    const finalImageUrls = uploadedImageUrls.length ? uploadedImageUrls : inputImageUrls;
+    const finalImageVariants = uploadedImageVariants.length ? uploadedImageVariants : [];
    const finalVideoUrl = uploadedVideoUrl || dto.videoUrl || '';
    const finalAudioUrl = uploadedAudioUrl || dto.audioUrl || '';
    const finalContent = dto.content?.trim() ?? '';
@@ -128,9 +143,11 @@ export class PostsService {
      post = await this.postsRepository.create(userId, {
        content: finalContent,
        imageUrls: finalImageUrls,
+        imageVariants: finalImageVariants,
        videoUrl: finalVideoUrl,
        hlsUrl: uploadedHlsUrl,
        audioUrl: finalAudioUrl,
+        thumbnailVariants: uploadedThumbnailVariants,
        taggedUserIds,
        mentionUsernames: mentionResolution.mentionUsernames,
        location,
@@ -143,10 +160,12 @@ export class PostsService {
      });
    } catch (error) {
      await Promise.all([
-        ...uploadedImageUrls.map((url) => this.deleteManagedPostMedia(url)),
+        ...savedImageUploads.map((item) => this.deleteSavedImageAsset(item)),
        uploadedVideoUrl ? this.deleteManagedPostMedia(uploadedVideoUrl) : Promise.resolve(),
        uploadedHlsUrl ? this.storageService.deleteContainingDirectory(uploadedHlsUrl) : Promise.resolve(),
-        uploadedThumbnailUrl ? this.deleteManagedPostMedia(uploadedThumbnailUrl) : Promise.resolve(),
+        uploadedThumbnailUrl
+          ? this.deleteThumbnailAsset(uploadedThumbnailUrl, uploadedThumbnailVariants)
+          : Promise.resolve(),
        uploadedAudioUrl ? this.deleteManagedPostMedia(uploadedAudioUrl) : Promise.resolve(),
      ]);
      throw error;
@@ -199,13 +218,21 @@ export class PostsService {
      throw new BadRequestException('Post can contain either images or audio, not both');
    }

-    const uploadedImageUrls = await this.saveImageFiles(imageFiles);
+    const savedImageUploads = await this.saveImageFiles(imageFiles);
+    const uploadedImageUrls = savedImageUploads.map((item) => item.primaryUrl);
+    const uploadedImageVariants = savedImageUploads.map((item) => item.variants);
    const savedVideoUpload = videoFile ? await this.saveVideoUpload(videoFile) : null;
    const uploadedVideoUrl = savedVideoUpload?.videoUrl ?? '';
    const uploadedHlsUrl = savedVideoUpload?.hlsUrl ?? '';
    const uploadedThumbnailUrl = savedVideoUpload?.thumbnailUrl ?? '';
+    const uploadedThumbnailVariants = savedVideoUpload?.thumbnailVariants ?? null;
    const uploadedAudioUrl = audioFile ? await this.saveMediaFile('audio', audioFile) : '';
    const hasImageUpdate = typeof dto.imageUrls !== 'undefined' || imageFiles.length > 0;
+    const existingImageVariants = Array.isArray((post as any).imageVariants)
+      ? (((post as any).imageVariants ?? []) as PostMediaVariantSet[])
+      : [];
+    const existingThumbnailVariants =
+      ((post as any).thumbnailVariants as PostMediaVariantSet | null | undefined) ?? null;

    const hasVideoUpdate = typeof dto.videoUrl !== 'undefined' || !!videoFile;
    const hasAudioUpdate = typeof dto.audioUrl !== 'undefined' || !!audioFile;
@@ -214,6 +241,11 @@ export class PostsService {
        ? uploadedImageUrls
        : inputImageUrls
      : post.imageUrls ?? [];
+    const nextImageVariants = hasImageUpdate
+      ? imageFiles.length
+        ? uploadedImageVariants
+        : []
+      : existingImageVariants;

    const nextVideoUrl = hasVideoUpdate
      ? videoFile
@@ -226,6 +258,11 @@ export class PostsService {
        ? uploadedAudioUrl
        : dto.audioUrl ?? ''
      : post.audioUrl ?? '';
+    const nextThumbnailVariants = videoFile
+      ? uploadedThumbnailVariants
+      : typeof dto.thumbnailUrl === 'string'
+        ? null
+        : existingThumbnailVariants;
    const nextPostType = this.resolvePostType(nextImageUrls, nextVideoUrl, nextAudioUrl);
    const nextContent = typeof dto.content === 'string' ? dto.content.trim() : post.content ?? '';
    const nextTaggedUserIds =
@@ -272,7 +309,9 @@ export class PostsService {
      ...dto,
      content: nextContent,
      imageUrls: nextImageUrls,
+      imageVariants: nextImageVariants,
      hlsUrl: nextHlsUrl,
+      thumbnailVariants: nextThumbnailVariants,
      taggedUserIds: nextTaggedUserIds,
      mentionUsernames: mentionResolution.mentionUsernames,
      location: nextLocation,
@@ -300,40 +339,51 @@ export class PostsService {
      payload.videoUrl = '';
      payload.audioUrl = '';
      payload.hlsUrl = '';
+      payload.thumbnailVariants = null;
    }

    if (videoFile) {
      payload.videoUrl = uploadedVideoUrl;
      payload.hlsUrl = uploadedHlsUrl;
+      payload.thumbnailVariants = uploadedThumbnailVariants;
      payload.imageUrls = [];
+      payload.imageVariants = [];
      payload.audioUrl = '';
    }
    if (audioFile) {
      payload.audioUrl = uploadedAudioUrl;
      payload.imageUrls = [];
+      payload.imageVariants = [];
      payload.videoUrl = '';
      payload.hlsUrl = '';
    }
+    if (nextPostType !== PostType.AUDIO && nextPostType !== PostType.VIDEO) {
+      payload.thumbnailVariants = null;
+    }

    let updated: PostDocument | null;
    try {
      updated = await this.postsRepository.updateById(postId, payload as any);
    } catch (error) {
      await Promise.all([
-        ...uploadedImageUrls.map((url) => this.deleteManagedPostMedia(url)),
+        ...savedImageUploads.map((item) => this.deleteSavedImageAsset(item)),
        uploadedVideoUrl ? this.deleteManagedPostMedia(uploadedVideoUrl) : Promise.resolve(),
        uploadedHlsUrl ? this.storageService.deleteContainingDirectory(uploadedHlsUrl) : Promise.resolve(),
-        uploadedThumbnailUrl ? this.deleteManagedPostMedia(uploadedThumbnailUrl) : Promise.resolve(),
+        uploadedThumbnailUrl
+          ? this.deleteThumbnailAsset(uploadedThumbnailUrl, uploadedThumbnailVariants)
+          : Promise.resolve(),
        uploadedAudioUrl ? this.deleteManagedPostMedia(uploadedAudioUrl) : Promise.resolve(),
      ]);
      throw error;
    }
    if (!updated) {
      await Promise.all([
-        ...uploadedImageUrls.map((url) => this.deleteManagedPostMedia(url)),
+        ...savedImageUploads.map((item) => this.deleteSavedImageAsset(item)),
        uploadedVideoUrl ? this.deleteManagedPostMedia(uploadedVideoUrl) : Promise.resolve(),
        uploadedHlsUrl ? this.storageService.deleteContainingDirectory(uploadedHlsUrl) : Promise.resolve(),
-        uploadedThumbnailUrl ? this.deleteManagedPostMedia(uploadedThumbnailUrl) : Promise.resolve(),
+        uploadedThumbnailUrl
+          ? this.deleteThumbnailAsset(uploadedThumbnailUrl, uploadedThumbnailVariants)
+          : Promise.resolve(),
        uploadedAudioUrl ? this.deleteManagedPostMedia(uploadedAudioUrl) : Promise.resolve(),
      ]);
      throw new NotFoundException('Post not found');
@@ -346,17 +396,18 @@ export class PostsService {
      await this.storageService.deleteContainingDirectory(post.hlsUrl ?? '');
    }
    if ((post.thumbnailUrl ?? '') !== (updated.thumbnailUrl ?? '')) {
-      await this.deleteManagedPostMedia(post.thumbnailUrl ?? '');
+      await this.deleteThumbnailAsset(post.thumbnailUrl ?? '', existingThumbnailVariants);
    }
    if (hasAudioUpdate && (post.audioUrl ?? '') !== (updated.audioUrl ?? '')) {
      await this.deleteManagedPostMedia(post.audioUrl ?? '');
    }
    if (hasImageUpdate) {
      const nextImageSet = new Set(updated.imageUrls ?? []);
+      const existingImageAssets = this.buildSavedImageAssets(post.imageUrls ?? [], existingImageVariants);
      await Promise.all(
-        (post.imageUrls ?? [])
-          .filter((url) => !nextImageSet.has(url))
-          .map((url) => this.deleteManagedPostMedia(url)),
+        existingImageAssets
+          .filter((asset) => !nextImageSet.has(asset.primaryUrl))
+          .map((asset) => this.deleteSavedImageAsset(asset)),
      );
    }

@@ -382,11 +433,19 @@ export class PostsService {
    }

    await this.postsRepository.deleteById(postId, userId);
+    const existingImageVariants = Array.isArray((post as any).imageVariants)
+      ? (((post as any).imageVariants ?? []) as PostMediaVariantSet[])
+      : [];
+    const existingThumbnailVariants =
+      ((post as any).thumbnailVariants as PostMediaVariantSet | null | undefined) ?? null;
    await Promise.all([
-      ...(post.imageUrls ?? []).map((url) => this.deleteManagedPostMedia(url)),
+      ...this.buildSavedImageAssets(post.imageUrls ?? [], existingImageVariants).map((asset) =>
+        this.deleteSavedImageAsset(asset),
+      ),
      this.deleteManagedPostMedia(post.videoUrl ?? ''),
      this.storageService.deleteContainingDirectory(post.hlsUrl ?? ''),
      this.deleteManagedPostMedia(post.audioUrl ?? ''),
+      this.deleteThumbnailAsset(post.thumbnailUrl ?? '', existingThumbnailVariants),
    ]);
    await this.usersRepository.incrementPostsCount(userId, -1);
    await this.feedVersionService.bumpGlobalVersion();
@@ -623,12 +682,20 @@ export class PostsService {
      throw new NotFoundException('Post not found');
    }

+    const existingImageVariants = Array.isArray((post as any).imageVariants)
+      ? (((post as any).imageVariants ?? []) as PostMediaVariantSet[])
+      : [];
+    const existingThumbnailVariants =
+      ((post as any).thumbnailVariants as PostMediaVariantSet | null | undefined) ?? null;
    await this.postsRepository.deleteById(postId, superAdminIdentifier);
    await Promise.all([
-      ...(post.imageUrls ?? []).map((url) => this.deleteManagedPostMedia(url)),
+      ...this.buildSavedImageAssets(post.imageUrls ?? [], existingImageVariants).map((asset) =>
+        this.deleteSavedImageAsset(asset),
+      ),
      this.deleteManagedPostMedia(post.videoUrl ?? ''),
      this.storageService.deleteContainingDirectory(post.hlsUrl ?? ''),
      this.deleteManagedPostMedia(post.audioUrl ?? ''),
+      this.deleteThumbnailAsset(post.thumbnailUrl ?? '', existingThumbnailVariants),
    ]);
    const authorId = this.extractEntityId(post.authorId);
    if (authorId) {
@@ -938,6 +1005,7 @@ export class PostsService {
    let videoUrl = '';
    let hlsUrl = '';
    let thumbnailUrl = '';
+    let thumbnailVariants: PostMediaVariantSet | null = null;
    const hlsFolderName = `stream-${new Types.ObjectId().toString()}`;

    try {
@@ -958,21 +1026,22 @@ export class PostsService {
      }

      if (optimized.generatedThumbnail) {
-        thumbnailUrl = await this.storageService.saveFile({
-          folderSegments: ['posts', 'thumbnails'],
-          extension: optimized.generatedThumbnail.extension,
+        const savedThumbnail = await this.saveResponsiveImageAsset('thumbnails', {
          buffer: optimized.generatedThumbnail.buffer,
-          contentType: optimized.generatedThumbnail.contentType,
-          fileNamePrefix: 'thumbnail',
+          size: optimized.generatedThumbnail.buffer.length,
+          mimetype: optimized.generatedThumbnail.contentType,
+          originalname: `thumbnail${optimized.generatedThumbnail.extension}`,
        });
+        thumbnailUrl = savedThumbnail.primaryUrl;
+        thumbnailVariants = savedThumbnail.variants;
      }

-      return { videoUrl, hlsUrl, thumbnailUrl };
+      return { videoUrl, hlsUrl, thumbnailUrl, thumbnailVariants };
    } catch (error) {
      await Promise.all([
        videoUrl ? this.deleteManagedPostMedia(videoUrl) : Promise.resolve(),
        hlsUrl ? this.storageService.deleteContainingDirectory(hlsUrl) : Promise.resolve(),
-        thumbnailUrl ? this.deleteManagedPostMedia(thumbnailUrl) : Promise.resolve(),
+        thumbnailUrl ? this.deleteThumbnailAsset(thumbnailUrl, thumbnailVariants) : Promise.resolve(),
      ]);
      throw error;
    }
@@ -1097,7 +1166,7 @@ export class PostsService {

  private async saveImageFiles(
    files: Array<{ mimetype?: string; size: number; buffer: Buffer; originalname?: string }>,
-  ): Promise<string[]> {
+  ): Promise<SavedImageUpload[]> {
    if (!files.length) {
      return [];
    }
@@ -1105,18 +1174,150 @@ export class PostsService {
      throw new BadRequestException('Post can contain up to 10 images');
    }

-    const urls: string[] = [];
+    const uploads: SavedImageUpload[] = [];
    try {
      for (const file of files) {
-        urls.push(await this.saveMediaFile('image', file));
+        uploads.push(await this.saveResponsiveImageAsset('images', file));
      }
-      return urls;
+      return uploads;
    } catch (error) {
-      await Promise.all(urls.map((url) => this.deleteManagedPostMedia(url)));
+      await Promise.all(uploads.map((upload) => this.deleteSavedImageAsset(upload)));
      throw error;
    }
  }

+  private async saveResponsiveImageAsset(
+    folder: 'images' | 'thumbnails',
+    file: UploadedImageFile,
+  ): Promise<SavedImageUpload> {
+    this.validateMediaFile('image', file);
+    const processed = await this.imageProcessingService.processForResponsiveDelivery(file);
+    const groupName = `${folder.slice(0, -1)}-${new Types.ObjectId().toString()}`;
+    const savedFiles = await this.storageService.saveFiles({
+      folderSegments: ['posts', folder, groupName],
+      files: processed.variants.map((variant) => ({
+        relativePath: variant.relativePath,
+        buffer: variant.buffer,
+        contentType: variant.contentType,
+      })),
+    });
+
+    const variants = this.buildVariantSet(processed, savedFiles);
+    return {
+      primaryUrl: this.resolvePrimaryVariantUrl(variants, processed.primaryVariantName),
+      variants,
+    };
+  }
+
+  private buildVariantSet(
+    processed: Awaited<ReturnType<ImageProcessingService['processForResponsiveDelivery']>>,
+    savedFiles: Record<string, string>,
+  ): PostMediaVariantSet {
+    const byName = new Map(
+      processed.variants.map((variant) => [variant.name, savedFiles[variant.relativePath] ?? '']),
+    );
+    const originalUrl = byName.get('original') ?? '';
+    const lowUrl = byName.get('low') ?? originalUrl;
+    const mediumUrl = byName.get('medium') ?? byName.get('high') ?? lowUrl;
+    const highUrl = byName.get('high') ?? mediumUrl ?? lowUrl;
+
+    return {
+      originalUrl,
+      lowUrl,
+      mediumUrl,
+      highUrl,
+    };
+  }
+
+  private resolvePrimaryVariantUrl(
+    variants: PostMediaVariantSet,
+    preferredVariantName: 'original' | 'low' | 'medium' | 'high',
+  ): string {
+    const candidates =
+      preferredVariantName === 'low'
+        ? [variants.lowUrl, variants.mediumUrl, variants.highUrl, variants.originalUrl]
+        : preferredVariantName === 'high'
+          ? [variants.highUrl, variants.mediumUrl, variants.lowUrl, variants.originalUrl]
+          : preferredVariantName === 'original'
+            ? [variants.originalUrl, variants.highUrl, variants.mediumUrl, variants.lowUrl]
+            : [variants.mediumUrl, variants.highUrl, variants.lowUrl, variants.originalUrl];
+
+    return candidates.find((candidate) => !!candidate) ?? '';
+  }
+
+  private buildSavedImageAssets(
+    imageUrls: string[],
+    imageVariants: PostMediaVariantSet[] = [],
+  ): SavedImageUpload[] {
+    return imageUrls.map((primaryUrl, index) => ({
+      primaryUrl,
+      variants: imageVariants[index] ?? this.buildFlatVariantSet(primaryUrl),
+    }));
+  }
+
+  private buildFlatVariantSet(primaryUrl: string): PostMediaVariantSet {
+    return {
+      originalUrl: primaryUrl,
+      lowUrl: primaryUrl,
+      mediumUrl: primaryUrl,
+      highUrl: primaryUrl,
+    };
+  }
+
+  private async deleteSavedImageAsset(upload: SavedImageUpload): Promise<void> {
+    const anchorUrl =
+      upload.variants.mediumUrl ||
+      upload.variants.highUrl ||
+      upload.variants.lowUrl ||
+      upload.variants.originalUrl ||
+      upload.primaryUrl;
+
+    const hasManagedVariantGroup = [
+      upload.variants.originalUrl,
+      upload.variants.lowUrl,
+      upload.variants.mediumUrl,
+      upload.variants.highUrl,
+    ].some((url) => !!url && url !== upload.primaryUrl);
+
+    if (anchorUrl && hasManagedVariantGroup) {
+      await this.storageService.deleteContainingDirectory(anchorUrl);
+      return;
+    }
+
+    await this.deleteManagedPostMedia(upload.primaryUrl);
+  }
+
+  private async deleteThumbnailAsset(
+    thumbnailUrl: string,
+    thumbnailVariants: PostMediaVariantSet | null,
+  ): Promise<void> {
+    if (!thumbnailUrl) {
+      return;
+    }
+
+    const anchorUrl =
+      thumbnailVariants?.mediumUrl ||
+      thumbnailVariants?.highUrl ||
+      thumbnailVariants?.lowUrl ||
+      thumbnailVariants?.originalUrl ||
+      '';
+
+    const hasManagedVariantGroup = !!thumbnailVariants &&
+      [
+        thumbnailVariants.originalUrl,
+        thumbnailVariants.lowUrl,
+        thumbnailVariants.mediumUrl,
+        thumbnailVariants.highUrl,
+      ].some((url) => !!url && url !== thumbnailUrl);
+
+    if (anchorUrl && hasManagedVariantGroup) {
+      await this.storageService.deleteContainingDirectory(anchorUrl);
+      return;
+    }
+
+    await this.deleteManagedPostMedia(thumbnailUrl);
+  }
+
  private async deleteManagedPostMedia(fileUrl: string): Promise<void> {
    await this.storageService.deleteFile(fileUrl);
  }
--- a/src/modules/posts/schemas/post.schema.ts
+++ b/src/modules/posts/schemas/post.schema.ts
@@ -1,16 +1,32 @@
-import { Prop, Schema, SchemaFactory } from '@nestjs/mongoose';
+import { Prop, Schema, SchemaFactory, raw } from '@nestjs/mongoose';
 import { HydratedDocument, Types } from 'mongoose';
 import { ModerationStatus } from '../../../common/enums/moderation-status.enum';
 import { PostType } from '../../../common/enums/post-type.enum';
 import { PostVisibility } from '../../../common/enums/post-visibility.enum';
 import {
  resolveManagedFileUrl,
+  resolveManagedFileUrlRecord,
+  resolveManagedFileUrlRecords,
  resolveManagedFileUrls,
 } from '../../../common/utils/public-url.util';
 import { User } from '../../users/schemas/user.schema';

 export type PostDocument = HydratedDocument<Post>;

+export type PostMediaVariantSet = {
+  originalUrl: string;
+  lowUrl: string;
+  mediumUrl: string;
+  highUrl: string;
+};
+
+const mediaVariantSetSchema = raw({
+  originalUrl: { type: String, default: '' },
+  lowUrl: { type: String, default: '' },
+  mediumUrl: { type: String, default: '' },
+  highUrl: { type: String, default: '' },
+});
+
@Schema({ timestamps: true, versionKey: false })
 export class Post {
  @Prop({ type: Types.ObjectId, ref: User.name, required: true, index: true })
@@ -34,6 +50,9 @@ export class Post {
  @Prop({ default: '' })
  thumbnailUrl!: string;

+  @Prop({ type: mediaVariantSetSchema, default: null })
+  thumbnailVariants!: PostMediaVariantSet | null;
+
  @Prop({ default: '', trim: true, maxlength: 80 })
  style!: string;

@@ -49,6 +68,9 @@ export class Post {
  @Prop({ type: [String], default: [] })
  imageUrls!: string[];

+  @Prop({ type: [mediaVariantSetSchema], default: [] })
+  imageVariants!: PostMediaVariantSet[];
+
  @Prop({ type: [Types.ObjectId], ref: User.name, default: [], index: true })
  taggedUserIds!: Types.ObjectId[];

@@ -136,10 +158,12 @@ PostSchema.index({

 const transformManagedPostFiles = (_doc: unknown, ret: any) => {
  ret.imageUrls = resolveManagedFileUrls(ret.imageUrls);
+  ret.imageVariants = resolveManagedFileUrlRecords(ret.imageVariants);
  ret.videoUrl = resolveManagedFileUrl(ret.videoUrl);
  ret.hlsUrl = resolveManagedFileUrl(ret.hlsUrl);
  ret.audioUrl = resolveManagedFileUrl(ret.audioUrl);
  ret.thumbnailUrl = resolveManagedFileUrl(ret.thumbnailUrl);
+  ret.thumbnailVariants = resolveManagedFileUrlRecord(ret.thumbnailVariants);
  return ret;
 };