diff --git a/lib/OpenLayers/Layer.js b/lib/OpenLayers/Layer.js
index 7b22973f2a..e360584489 100644
--- a/lib/OpenLayers/Layer.js
+++ b/lib/OpenLayers/Layer.js
@@ -555,12 +555,17 @@ OpenLayers.Layer = OpenLayers.Class({
     
     /**
      * APIMethod: getImageSize
+     *
+     * Parameters:
+     * bounds - {<OpenLayers.Bounds>} optional tile bounds, can be used
+     *     by subclasses that have to deal with different tile sizes at the
+     *     layer extent edges (e.g. Zoomify)
      * 
      * Returns:
      * {<OpenLayers.Size>} The size that the image should be, taking into 
      *     account gutters.
      */ 
-    getImageSize: function() { 
+    getImageSize: function(bounds) { 
         return (this.imageSize || this.tileSize); 
     },    
   
diff --git a/lib/OpenLayers/Tile/Image.js b/lib/OpenLayers/Tile/Image.js
index ac89ed2cf7..1e400100fe 100644
--- a/lib/OpenLayers/Tile/Image.js
+++ b/lib/OpenLayers/Tile/Image.js
@@ -263,7 +263,7 @@ OpenLayers.Tile.Image = OpenLayers.Class(OpenLayers.Tile, {
                 this.backBufferTile.position = this.position;
                 this.backBufferTile.bounds = this.bounds;
                 this.backBufferTile.size = this.size;
-                this.backBufferTile.imageSize = this.layer.imageSize || this.size;
+                this.backBufferTile.imageSize = this.layer.getImageSize(this.bounds) || this.size;
                 this.backBufferTile.imageOffset = this.layer.imageOffset;
                 this.backBufferTile.resolution = this.layer.getResolution();
                 this.backBufferTile.renderTile();
@@ -324,7 +324,7 @@ OpenLayers.Tile.Image = OpenLayers.Class(OpenLayers.Tile, {
         OpenLayers.Util.modifyDOMElement(this.frame, 
                                           null, this.position, this.size);   
 
-        var imageSize = this.layer.getImageSize(); 
+        var imageSize = this.layer.getImageSize(this.bounds); 
         if (this.layerAlphaHack) {
             OpenLayers.Util.modifyAlphaImageDiv(this.imgDiv,
                     null, null, imageSize, this.url);
@@ -356,7 +356,7 @@ OpenLayers.Tile.Image = OpenLayers.Class(OpenLayers.Tile, {
     initImgDiv: function() {
         
         var offset = this.layer.imageOffset; 
-        var size = this.layer.getImageSize(); 
+        var size = this.layer.getImageSize(this.bounds); 
      
         if (this.layerAlphaHack) {
             this.imgDiv = OpenLayers.Util.createAlphaImageDiv(null,