reverting again - this time I broke things in Opera (see #3419)

git-svn-id: http://svn.openlayers.org/trunk/openlayers@12246 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Tile/Image.js

@@ -274,19 +274,9 @@ OpenLayers.Tile.Image = OpenLayers.Class(OpenLayers.Tile.BackBufferable, {
      * url - {String} or undefined to hide the image
      */
     setImgSrc: function(url) {
-        var img = this.imgDiv;
+        this.imgDiv.style.display = "none";
-        img.style.display = "none";
-        // Setting img.src to "about:blank" would cause a broken image icon in
-        // some browsers, but we only use it when style.display is set to
-        // "none", so we don't care. We need this to prevent old images or
-        // loading image placeholders to be shown when the image's display style
-        // is set to "" in the onImageLoad method, which is called just before
-        // the image is rendered in some browsers. Note that setting img.src to
-        // "" would cause a request for the current page location being sent to
-        // the server in most browsers.
-        img.src = "about:blank";
         if (url) {
-            img.src = url;
+            this.imgDiv.src = url;
         }
     },