thank you testing. only set this if a value is passed in

git-svn-id: http://svn.openlayers.org/trunk/openlayers@151 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Util.js

@@ -613,7 +613,9 @@ OpenLayers.Util.createImage = function(img, sz, xy, position, id, border) {
         image.style.border = 0;
     }
     image.style.cursor = "inherit";
-    image.src = img;
+    if (img) {
+        image.src = img;
+    }
     image.galleryImg = "no";
     
     return image;