Index: lib/OpenLayers/Tile/Image.js
===================================================================
--- lib/OpenLayers/Tile/Image.js	(revision 9332)
+++ lib/OpenLayers/Tile/Image.js	(working copy)
@@ -122,7 +122,8 @@
                 this.imgDiv.map = null;
             }
             this.imgDiv.urls = null;
-            this.imgDiv.src = null;
+            // abort any currently loading image
+            this.imgDiv.src = OpenLayers.Util.getImagesLocation() + "blank.gif";
         }
         this.imgDiv = null;
         if ((this.frame != null) && (this.frame.parentNode == this.layer.div)) {