diff --git a/native/media/image-utils.js b/native/media/image-utils.js
--- a/native/media/image-utils.js
+++ b/native/media/image-utils.js
@@ -13,11 +13,12 @@
 import { generateThumbhashStep } from './media-utils.js';
 
 type ProcessImageInfo = {
-  uri: string,
-  dimensions: Dimensions,
-  mime: string,
-  fileSize: number,
-  orientation: ?number,
+  +uri: string,
+  +filesystemURI: string,
+  +dimensions: Dimensions,
+  +mime: string,
+  +fileSize: number,
+  +orientation: ?number,
 };
 type ProcessImageResponse = {
   success: true,
@@ -33,7 +34,7 @@
   const steps: Array<MediaMissionStep> = [];
   let { uri, dimensions, mime } = input;
 
-  const { fileSize, orientation } = input;
+  const { fileSize, orientation, filesystemURI } = input;
   const plan = getImageProcessingPlan({
     inputMIME: mime,
     inputDimensions: dimensions,
@@ -41,7 +42,7 @@
     inputOrientation: orientation,
   });
   if (plan.action === 'none') {
-    const thumbhashStep = await generateThumbhashStep(uri);
+    const thumbhashStep = await generateThumbhashStep(filesystemURI);
     steps.push(thumbhashStep);
     const { thumbHash } = thumbhashStep;
     return {
diff --git a/native/media/media-utils.js b/native/media/media-utils.js
--- a/native/media/media-utils.js
+++ b/native/media/media-utils.js
@@ -197,8 +197,8 @@
   if (mediaType === 'video') {
     const { steps: videoSteps, result: videoResult } = await processVideo(
       {
-        // we pass selection.uri, because for processing videos filesystem
-        // uris don't work due to permissions
+        // We pass in selection.uri because our iOS transcoding module seems to
+        // have permission issues when passed a filesystem URI
         uri: selection.uri,
         mime,
         filename: selection.filename,
@@ -224,8 +224,13 @@
     } = videoResult);
   } else if (mediaType === 'photo') {
     const { steps: imageSteps, result: imageResult } = await processImage({
-      // we pass selection.uri for consistency with videos
+      // We pass in selection.uri so that the returned imageResult.uri can be
+      // compared to selection.uri to determine if any processing occurred.
+      // processImage would be fine taking fileInfoResult.uri instead, but
+      // processVideo can't, which would force us to make the comparison below
+      // different in the image vs. video case
       uri: selection.uri,
+      filesystemURI: fileInfoResult.uri,
       dimensions,
       mime,
       fileSize,