code: function(id, lonlat, contentSize, contentHTML, anchor, closeBox, 
                          closeBoxCallback) {
  
          this.imageSrc = OpenLayers.Util.getImageLocation('cloud-popup-relative.png');
          OpenLayers.Popup.Framed.prototype.initialize.apply(this, arguments);
          this.contentDiv.className = this.contentDisplayClass;
      }
docs: Constructor: OpenLayers.Popup.FramedCloud
  
  Parameters:
  id - {String}
  lonlat - {<OpenLayers.LonLat>}
  contentSize - {<OpenLayers.Size>}
  contentHTML - {String}
  anchor - {Object} Object to which we'll anchor the popup. Must expose
  a 'size' (<OpenLayers.Size>) and 'offset' (<OpenLayers.Pixel>)
  (Note that this is generally an <OpenLayers.Icon>).
  closeBox - {Boolean}
  closeBoxCallback - {Function} Function to be called on closeBox click.