var Rollovers = function(opt){
		  var o = opt;
		  var load = function() {
		    $A(o.selector).each(function(s) {
		      $$(s).each(
		        function(i) {
		          var os = i.src, ni = document.createElement('img');
		          $(i).observe('mouseout', function(e){i.src = os;});
		          ni.src = o.srcFunction(i,o);
		          i.observe('mouseover', function(e){i.src = ni.src;});
		        }
		      );
		    });
		  };
		  if(window.FastInit) {
		  	FastInit.addOnLoad(load);
		  } else {
		  	Event.observe(window, 'load', load);
		  }
		}
		Rollovers({
		  selector : ['img.rollover'],
		  srcFunction : function(i, o) {
		    return i.src.replace(/(.*)\.(jpg|gif|png)$/i, "$1_over.$2");
		  }
		});