apply patch-3531-A0.diff from trac ticket #3531

lib/OpenLayers/Tile/Image.js

@@ -187,10 +187,10 @@ OpenLayers.Tile.Image = OpenLayers.Class(OpenLayers.Tile.BackBufferable, {
      */
     positionTile: function() {
         var style = this.frame.style;
-        style.left = this.position.x + "px";
-        style.top = this.position.y + "px";
-        style.width = this.size.w + "px";
-        style.height = this.size.h + "px";
+        style.left = this.position.x + "%";
+        style.top = this.position.y + "%";
+        style.width = this.size.w + "%";
+        style.height = this.size.h + "%";
     },
 
     /** 
@@ -320,14 +320,16 @@ OpenLayers.Tile.Image = OpenLayers.Class(OpenLayers.Tile.BackBufferable, {
     },
 
     /**
-     * Method: createBackBuffer
-     * Create a copy of this tile's markup for the <layer>'s backBufferDiv
+     * Method: insertBackBuffer
+     * Create a copy of this tile's markup and insert it to the layer
+     * div.
      *
      * Returns:
-     * {DOMElement} a clone of the tile content
+     * {DOMElement} The back buffer.
      */
-    createBackBuffer: function() {
+    insertBackBuffer: function() {
         var frame = this.frame.cloneNode(false);
+        this.layer.div.insertBefore(frame, this.frame);
         frame.appendChild(this.imgDiv);
         this.imgDiv = null;
         return frame;