diff --git a/drafts/media_repository.rst b/drafts/media_repository.rst
index 25ef9dd6..879e1b85 100644
--- a/drafts/media_repository.rst
+++ b/drafts/media_repository.rst
@@ -52,7 +52,8 @@ within a given rectangle.
 Homeservers may generate thumbnails for content uploaded to remote
 homeservers themselves or may rely on the remote homeserver to thumbnail
 the content. Homeservers may return thumbnails of a different size to that
-requested. However homeservers should provide extact matches where reasonable.
+requested. However homeservers should provide exact matches where reasonable.
+Homeservers must never upscale images.
 
 Security
 --------