function startGalleryRotation(selector,delay){ 
 var i = 0; 
 var layers = $$(selector); 
 delay = (delay == undefined)? 6000:delay; 
 setInterval(function(){ 
  layers[i].fade('out'); 
  i = (i == layers.length-1)? 0 : i+1; 
  layers[i].fade('in'); 
 },delay); 
}; 

 window.addEvent('load', function(){
  startGalleryRotation('#rimage div',3000);
 });