diff --git a/lib/src/client.dart b/lib/src/client.dart
index f856d334..69051895 100644
--- a/lib/src/client.dart
+++ b/lib/src/client.dart
@@ -842,7 +842,7 @@ class Client extends MatrixApi {
   static const List<String> supportedGroupEncryptionAlgorithms = [
     AlgorithmTypes.megolmV1AesSha2
   ];
-  static const int defaultThumbnailSize = 256;
+  static const int defaultThumbnailSize = 800;
 
   /// The newEvent signal is the most important signal in this concept. Every time
   /// the app receives a new synchronization, this event is called for every signal