code: function (bounds) {
          bounds = this.adjustBounds(bounds);
  
          // ArcGIS Server only wants the numeric portion of the projection ID.
          var projWords = this.projection.getCode().split(":");
          var srid = projWords[projWords.length - 1];
  
          var imageSize = this.getImageSize(); 
          var newParams = {
              'BBOX': bounds.toBBOX(),
              'SIZE': imageSize.w + "," + imageSize.h,
              // We always want image, the other options were json, image with a whole lotta html around it, etc.
              'F': "image",
              'BBOXSR': srid,
              'IMAGESR': srid
          };
  
          // Now add the filter parameters.
          if (this.layerDefs) {
              var layerDefStrList = [];
              var layerID;
              for(layerID in this.layerDefs) {
                  if (this.layerDefs.hasOwnProperty(layerID)) {
                      if (this.layerDefs[layerID]) {
                          layerDefStrList.push(layerID);
                          layerDefStrList.push(":");
                          layerDefStrList.push(this.layerDefs[layerID]);
                          layerDefStrList.push(";");
                      }
                  }
              }
              if (layerDefStrList.length > 0) {
                  newParams['LAYERDEFS'] = layerDefStrList.join("");
              }
          }
          var requestString = this.getFullRequestString(newParams);
          return requestString;
      }
docs: Method: getURL
  Return an image url this layer.
  
  Parameters:
  bounds - {<OpenLayers.Bounds>} A bounds representing the bbox for the
  request.
  
  Returns:
  {String} A string with the map image's url.