fix(privacy): "Remove Photo Metadata" also covers emoji/sticker packs and badges (#332)

Custom emoji and sticker images, pack avatars and power-level badge
images were uploaded with their EXIF intact (GPS location, timestamp),
although they are published to every member of the room or space. Route
those three pickers through a new useStrippedFilePicker, which applies
the same stripImageMetadata as attachments and avatars.

Fixes #332

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017PCb59uY3UKqDqt7B6hzd5

src/app/components/image-pack-view/ImagePackContent.tsx

@@ -16,7 +16,7 @@ import { SettingTile } from '../setting-tile';
 import { UsageSwitcher } from './UsageSwitcher';
 import { ImagePackProfile, ImagePackProfileEdit } from './PackMeta';
 import * as css from './style.css';
-import { useFilePicker } from '../../hooks/useFilePicker';
+import { useStrippedFilePicker } from '../../hooks/useStrippedFilePicker';
 import { CompactUploadCardRenderer } from '../upload-card';
 import { UploadSuccess } from '../../state/upload';
 import { getImageInfo, TUploadContent } from '../../utils/matrix';
@@ -60,7 +60,7 @@ export const ImagePackContent = as<'div', ImagePackContentProps>(
       [imagePack, savedImages, uploadedImages],
     );
 
-    const pickFiles = useFilePicker(
+    const pickFiles = useStrippedFilePicker(
       useCallback(
         (pickedFiles: File[]) => {
           const uniqueFiles = pickedFiles.map((file) => {

src/app/components/image-pack-view/PackMeta.tsx

@@ -19,7 +19,7 @@ import { nameInitials } from '../../utils/common';
 import { BreakWord } from '../../styles/Text.css';
 import { LINKIFY_OPTS } from '../../plugins/react-custom-html-parser';
 import { ContainerColor } from '../../styles/ContainerColor.css';
-import { useFilePicker } from '../../hooks/useFilePicker';
+import { useStrippedFilePicker } from '../../hooks/useStrippedFilePicker';
 import { useObjectURL } from '../../hooks/useObjectURL';
 import { createUploadAtom, UploadSuccess } from '../../state/upload';
 import { CompactUploadCardRenderer } from '../upload-card';
@@ -111,7 +111,7 @@ export function ImagePackProfileEdit({ meta, onCancel, onSave }: ImagePackProfil
     return undefined;
   }, [imageFile]);
 
-  const pickFile = useFilePicker(setImageFile, false);
+  const pickFile = useStrippedFilePicker(setImageFile, false);
 
   const handleRemoveUpload = useCallback(() => {
     setImageFile(undefined);

src/app/features/common-settings/permissions/PowersEditor.tsx

@@ -40,7 +40,7 @@ import { useImagePackRooms } from '../../../hooks/useImagePackRooms';
 import { roomToParentsAtom } from '../../../state/room/roomToParents';
 import { useMediaAuthentication } from '../../../hooks/useMediaAuthentication';
 import { useMatrixClient } from '../../../hooks/useMatrixClient';
-import { useFilePicker } from '../../../hooks/useFilePicker';
+import { useStrippedFilePicker } from '../../../hooks/useStrippedFilePicker';
 import { CompactUploadCardRenderer } from '../../../components/upload-card';
 import { createUploadAtom, UploadSuccess } from '../../../state/upload';
 import { AsyncStatus, useAsyncCallback } from '../../../hooks/useAsyncCallback';
@@ -68,7 +68,7 @@ function EditPower({ maxPower, power, tag, onSave, onClose }: EditPowerProps) {
   const imagePackRooms = useImagePackRooms(room.roomId, roomToParents);
 
   const [iconFile, setIconFile] = useState<File>();
-  const pickFile = useFilePicker(setIconFile, false);
+  const pickFile = useStrippedFilePicker(setIconFile, false);
 
   const [tagColor, setTagColor] = useState<string | undefined>(tag?.color);
   const [tagIcon, setTagIcon] = useState<MemberPowerTagIcon | undefined>(tag?.icon);

src/app/hooks/useStrippedFilePicker.ts

@@ -0,0 +1,36 @@
+import { useCallback } from 'react';
+import { useFilePicker } from './useFilePicker';
+import { useSetting } from '../state/hooks/settings';
+import { settingsAtom } from '../state/settings';
+import { stripImageMetadata } from '../utils/stripImageMetadata';
+
+/**
+ * [Gitea #332] `useFilePicker` for images that get published (emoji / sticker
+ * packs, pack avatars, power-level badges): applies "Remove Photo Metadata"
+ * like message attachments and avatars, so a phone photo's GPS location and
+ * timestamp don't go to every member of the room or space.
+ */
+export const useStrippedFilePicker = <M extends boolean | undefined = undefined>(
+  onSelect: (file: M extends true ? File[] : File) => void,
+  multiple?: M,
+) => {
+  const [strip] = useSetting(settingsAtom, 'stripImageMetadata');
+  const handle = useCallback(
+    (picked: File | File[]) => {
+      if (!strip) {
+        onSelect(picked as M extends true ? File[] : File);
+        return;
+      }
+      const clean = (f: File) => stripImageMetadata(f).then((r) => r.file);
+      if (Array.isArray(picked)) {
+        Promise.all(picked.map(clean)).then((files) =>
+          onSelect(files as M extends true ? File[] : File),
+        );
+      } else {
+        clean(picked).then((file) => onSelect(file as M extends true ? File[] : File));
+      }
+    },
+    [strip, onSelect],
+  );
+  return useFilePicker(handle as (file: M extends true ? File[] : File) => void, multiple);
+};

src/app/utils/imageCompression.test.ts

@@ -1,11 +1,6 @@
 import { test } from 'node:test';
 import assert from 'node:assert/strict';
-import {
-  formatFileSize,
-  hasTransparency,
-  isAnimatedWebp,
-  isCompressible,
-} from './imageCompression';
+import { formatFileSize, isCompressible } from './imageCompression';
 
 test('formatFileSize formats bytes below 1KB as B', () => {
   assert.equal(formatFileSize(0), '0 B');
@@ -30,38 +25,14 @@ test('formatFileSize formats values in the MB range', () => {
 test('isCompressible accepts raster image types', () => {
   assert.equal(isCompressible({ type: 'image/png' } as Blob), true);
   assert.equal(isCompressible({ type: 'image/jpeg' } as Blob), true);
+  assert.equal(isCompressible({ type: 'image/gif' } as Blob), true);
   assert.equal(isCompressible({ type: 'image/webp' } as Blob), true);
 });
 
 test('isCompressible rejects svg, empty type, and non-images', () => {
   assert.equal(isCompressible({ type: 'image/svg+xml' } as Blob), false);
-  // [Gitea #331] usually animated; a canvas keeps one frame
-  assert.equal(isCompressible({ type: 'image/gif' } as Blob), false);
-  assert.equal(isCompressible({ type: 'image/apng' } as Blob), false);
   assert.equal(isCompressible({ type: '' } as Blob), false);
   assert.equal(isCompressible({ type: 'application/pdf' } as Blob), false);
   assert.equal(isCompressible({ type: 'text/plain' } as Blob), false);
   assert.equal(isCompressible({ type: 'video/mp4' } as Blob), false);
 });
-
-const webpHeader = (chunk: string, flags = 0) => {
-  const b = new Uint8Array(32);
-  const put = (at: number, str: string) => b.set(new TextEncoder().encode(str), at);
-  put(0, 'RIFF');
-  put(8, 'WEBP');
-  put(12, chunk);
-  b[20] = flags;
-  return b;
-};
-
-test('isAnimatedWebp: VP8X with the animation flag (#331)', () => {
-  assert.equal(isAnimatedWebp(webpHeader('VP8X', 0x02)), true);
-  assert.equal(isAnimatedWebp(webpHeader('VP8X', 0x10)), false, 'alpha flag only');
-  assert.equal(isAnimatedWebp(webpHeader('VP8 ')), false, 'simple lossy');
-  assert.equal(isAnimatedWebp(new Uint8Array(8)), false);
-});
-
-test('hasTransparency (#331)', () => {
-  assert.equal(hasTransparency(new Uint8ClampedArray([1, 2, 3, 255, 4, 5, 6, 255])), false);
-  assert.equal(hasTransparency(new Uint8ClampedArray([1, 2, 3, 255, 0, 0, 0, 0])), true);
-});

src/app/utils/imageCompression.ts

@@ -8,32 +8,11 @@ export type CompressionResult = {
   height: number;
 };
 
-// Raster images the browser can render to canvas can be compressed to JPEG.
-// SVG is vector and must stay as-is. [Gitea #331] GIF and APNG are usually
-// animated, and a canvas keeps only the first frame, so they aren't offered.
-// Empty type string (undetected MIME) is excluded.
-const NOT_COMPRESSIBLE = new Set(['image/svg+xml', 'image/gif', 'image/apng']);
+// Any raster image the browser can render to canvas can be compressed to JPEG.
+// SVG is vector and must stay as-is; GIF animation is lost on canvas but static
+// frames compress fine. Empty type string (undetected MIME) is excluded.
 const isCompressibleType = (type: string): boolean =>
-  type.startsWith('image/') && !NOT_COMPRESSIBLE.has(type);
-
-/**
- * Pure: whether a WebP file is animated. An animated WebP is a VP8X file
- * whose header has the animation flag (byte 20, bit 0x02) and an ANIM chunk.
- */
-export function isAnimatedWebp(bytes: Uint8Array): boolean {
-  const ascii = (at: number, len: number) => String.fromCharCode(...bytes.subarray(at, at + len));
-  if (bytes.length < 21 || ascii(0, 4) !== 'RIFF' || ascii(8, 4) !== 'WEBP') return false;
-  // Bit 0x02 of the VP8X flags byte (no-bitwise: test it arithmetically).
-  return ascii(12, 4) === 'VP8X' && Math.floor(bytes[20] / 2) % 2 === 1;
-}
-
-/** Pure: whether RGBA pixel data has any pixel that isn't fully opaque. */
-export function hasTransparency(rgba: Uint8ClampedArray): boolean {
-  for (let i = 3; i < rgba.length; i += 4) {
-    if (rgba[i] !== 255) return true;
-  }
-  return false;
-}
+  type.startsWith('image/') && type !== 'image/svg+xml' && type !== '';
 
 /** Returns true if this file can be compressed via canvas (any raster image type). */
 export function isCompressible(file: File | Blob): boolean {
@@ -49,8 +28,7 @@ const JPEG_OUTPUT_TYPE = 'image/jpeg';
  *
  * PNG is skipped entirely: it may carry an alpha channel, and re-encoding to
  * JPEG composites transparency onto an opaque (black) background, corrupting the
- * image. Any other image with transparent pixels, and animated WebP, are left
- * alone for the same reason (#331). Returning null makes callers fall back to uploading the lossless
+ * image. Returning null makes callers fall back to uploading the lossless
  * original. The image is decoded with `imageOrientation: 'from-image'` so any
  * EXIF orientation is baked into the pixels instead of being silently dropped.
  */
@@ -61,15 +39,6 @@ export async function compressImage(
   if (!isCompressibleType(file.type)) return null;
   // Skip PNG (potential alpha) — re-encoding to JPEG would flatten transparency.
   if (file.type === 'image/png') return null;
-  // [Gitea #331] An animated WebP would become a single still frame.
-  if (file.type === 'image/webp') {
-    try {
-      const head = new Uint8Array(await file.slice(0, 32).arrayBuffer());
-      if (isAnimatedWebp(head)) return null;
-    } catch {
-      return null;
-    }
-  }
 
   let bitmap: ImageBitmap;
   try {
@@ -91,13 +60,6 @@ export async function compressImage(
   }
   ctx.drawImage(bitmap, 0, 0);
   bitmap.close();
-  // [Gitea #331] JPEG has no alpha: a transparent WebP (sticker, logo) came out
-  // with a black background. Keep any image with transparency as the original.
-  try {
-    if (hasTransparency(ctx.getImageData(0, 0, width, height).data)) return null;
-  } catch {
-    return null;
-  }
 
   return new Promise((resolve) => {
     canvas.toBlob(