function rollOver() {
	var suffix1 = "_off.";
	var suffix2 = "_on.";

	var images = $$("img").concat($$("input")); 

	var tmp = new Object();
	images.each( function(obj, index) {
		obj.galleryImg = false;
		if(obj.getAttribute("src") && obj.getAttribute("src").indexOf(suffix1)!=-1) {
			obj.onmouseover = function() {
				this.setAttribute("src", this.getAttribute("src").replace(suffix1, suffix2));
			}
			obj.onmouseout = function() {
				this.setAttribute("src", this.getAttribute("src").replace(suffix2, suffix1));
			}
			tmp[index] = new Image();
			tmp[index].src = obj.src.replace(suffix1, suffix2);
		}
	} );
}

Event.observe(window, "load", rollOver, false);