diff --git a/repository/TiddlyWiki/Tiddler.class.st b/repository/TiddlyWiki/Tiddler.class.st
index 5585cc2..ecdcb90 100644
--- a/repository/TiddlyWiki/Tiddler.class.st
+++ b/repository/TiddlyWiki/Tiddler.class.st
@@ -308,7 +308,8 @@ Tiddler >> installTiddlerExporter [
 { #category : #testing }
 Tiddler >> isImage [
 
-	^ self type = 'image/'
+	^ self type ifNil: [ ^ false ];
+		beginsWith: 'image/'
 ]
 
 { #category : #testing }