diff --git a/lib/src/room.dart b/lib/src/room.dart
index 2038b71..d09581b 100644
--- a/lib/src/room.dart
+++ b/lib/src/room.dart
@@ -478,6 +478,7 @@ class Room {
     Event inReplyTo,
     Map<String, dynamic> info,
     bool waitUntilSent = false,
+    int thumbnailSize = Client.defaultThumbnailSize,
   }) async {
     Image fileImage;
     Image thumbnailImage;
@@ -506,7 +507,7 @@ class Room {
       thumbnailPathParts.last = 'thumbnail_' + thumbnailPathParts.last + '.jpg';
       final thumbnailPath = thumbnailPathParts.join('/');
       thumbnail = MatrixFile(bytes: file.bytes, path: thumbnailPath);
-      await thumbnail.resize(width: Client.defaultThumbnailSize);
+      await thumbnail.resize(width: thumbnailSize);
       fileImage = decodeImage(file.bytes.toList());
       thumbnailImage = decodeImage(thumbnail.bytes.toList());
     }