code: function(layer, position, bounds, url, size, options) {
          OpenLayers.Tile.prototype.initialize.apply(this, arguments);
  
          this.url = url; //deprecated remove me
          
          this.layerAlphaHack = this.layer.alpha && OpenLayers.Util.alphaHack();
  
          if (this.maxGetUrlLength != null || this.layer.gutter || this.layerAlphaHack) {
              // only create frame if it's needed
              this.frame = document.createElement("div");
              this.frame.style.position = "absolute";
              this.frame.style.overflow = "hidden";
          }
          if (this.maxGetUrlLength != null) {
              OpenLayers.Util.extend(this, OpenLayers.Tile.Image.IFrame);
          }
      }
docs: TBD 3.0 - reorder the parameters to the init function to remove
  URL. the getUrl() function on the layer gets called on
  each draw(), so no need to specify it here.
   
  Constructor: OpenLayers.Tile.Image
  Constructor for a new <OpenLayers.Tile.Image> instance.
  
  Parameters:
  layer - {<OpenLayers.Layer>} layer that the tile will go in.
  position - {<OpenLayers.Pixel>}
  bounds - {<OpenLayers.Bounds>}
  url - {<String>} Deprecated. Remove me in 3.0.
  size - {<OpenLayers.Size>}
  options - {Object}