Working version before modification.

public/js/images.js

@@ -4,8 +4,14 @@
  * during large-image processing. On browsers that lack OffscreenCanvas support
  * (or when running inside a Worker is not possible) the module falls back to
  * main-thread canvas operations.
+ *
+ * EXIF preservation: Canvas operations strip all metadata. After resize/compress
+ * we re-inject the original EXIF APP1 segment into the output JPEG so that
+ * camera info, GPS, date-taken etc. survive the optimization.
  */
 
+import { extractExifSegment, insertExifIntoJpeg } from './exif.js';
+
 let worker = null;
 let workerSupported = null;
 
@@ -35,6 +41,8 @@ function getWorker() {
 /*
  * Public entry point. Validates the file against the image rules, then delegates
  * the actual resize/compress work to the worker or the main-thread fallback.
+ * After optimization, EXIF metadata from the original file is re-injected into
+ * the output JPEG so that camera/GPS/date info is preserved.
  */
 export async function optimizeImage(file, imageRules) {
   if (imageRules?.allowedMimeTypes?.length && !imageRules.allowedMimeTypes.includes(file.type)) {
@@ -45,13 +53,26 @@ export async function optimizeImage(file, imageRules) {
     throw new Error(`File exceeds limit: ${file.name}`);
   }
 
-  const w = getWorker();
-
-  if (w) {
-    return optimizeInWorker(w, file, imageRules);
+  /* Extract raw EXIF segment from original JPEG before canvas strips it */
+  let exifSegment = null;
+  if (file.type === 'image/jpeg') {
+    try {
+      const originalBuffer = await file.arrayBuffer();
+      exifSegment = extractExifSegment(originalBuffer);
+    } catch { /* non-critical — proceed without EXIF */ }
   }
 
-  return optimizeOnMainThread(file, imageRules);
+  const w = getWorker();
+  const result = w
+    ? await optimizeInWorker(w, file, imageRules)
+    : await optimizeOnMainThread(file, imageRules);
+
+  /* Re-inject EXIF into the optimized JPEG */
+  if (exifSegment && result.blob.type === 'image/jpeg') {
+    result.blob = await insertExifIntoJpeg(result.blob, exifSegment);
+  }
+
+  return result;
 }
 
 /* ── Worker path ────────────────────────────────────────────────────────── */