code: private boolean isImage(I_CmsDraggable draggable) {
  
          return (draggable instanceof CmsResultListItem)
              && CmsToolbarAllGalleriesMenu.DND_MARKER.equals(((CmsResultListItem)draggable).getData());
  
      }
docs: Checks if the given draggable item is an image.<p>
  
  @param draggable the item to check
  
  @return true if the given item is an image