function Rollover() {	
	var imgarray=document.getElementsByTagName('img');
	var imgPreload=new Array();
	var imgSrc=new Array();
	var imgClass=new Array();
	for (i=0;i<imgarray.length;i++){
		if (imgarray[i].className.indexOf('roll')!=-1){
			imgSrc[i]=imgarray[i].getAttribute('src');
			imgClass[i]=imgarray[i].className;
			imgPreload[i]=new Image();
			if (imgClass[i].match(/roll (\S+)/)) {
				imgPreload[i].src = imgClass[i].match(/roll (\S+)/)[1]
			}
			imgarray[i].setAttribute('xsrc', imgSrc[i]);
			imgarray[i].onmouseover=function(){
				this.setAttribute('src',this.className.match(/roll (\S+)/)[1])
			}
			imgarray[i].onmouseout=function(){
				this.setAttribute('src',this.getAttribute('xsrc'))
			}
		}
	}
}
Rollover();