diff --git a/packages/stream_chat_flutter/CHANGELOG.md b/packages/stream_chat_flutter/CHANGELOG.md
index 42af3335..258e4cc5 100644
--- a/packages/stream_chat_flutter/CHANGELOG.md
+++ b/packages/stream_chat_flutter/CHANGELOG.md
@@ -4,6 +4,10 @@
 
 - `MessageInput` now works with a `MessageInputController` instead of a `TextEditingController`
 
+🐞 Fixed
+
+- Use file extension instead of mimeType for downloading files
+
 ✅ Added
 
 - Videos can now be auto-played in `FullScreenMedia`
diff --git a/packages/stream_chat_flutter/lib/src/attachment_actions_modal.dart b/packages/stream_chat_flutter/lib/src/attachment_actions_modal.dart
index 0c10ae46..ac9213b6 100644
--- a/packages/stream_chat_flutter/lib/src/attachment_actions_modal.dart
+++ b/packages/stream_chat_flutter/lib/src/attachment_actions_modal.dart
@@ -365,12 +365,13 @@ class AttachmentActionsModal extends StatelessWidget {
   }) async {
     String? filePath;
     final appDocDir = await getTemporaryDirectory();
+    final url =
+        attachment.assetUrl ?? attachment.imageUrl ?? attachment.thumbUrl!;
     await Dio().download(
-      attachment.assetUrl ?? attachment.imageUrl ?? attachment.thumbUrl!,
+      url,
       (Headers responseHeaders) {
-        final contentType = responseHeaders[Headers.contentTypeHeader]!;
-        final mimeType = contentType.first.split('/').last;
-        filePath ??= '${appDocDir.path}/${attachment.id}.$mimeType';
+        final ext = Uri.parse(url).pathSegments.last;
+        filePath ??= '${appDocDir.path}/${attachment.id}.$ext';
         return filePath!;
       },
       onReceiveProgress: progressCallback,