$(document).ready(function(){
	$(".roll").hover(
		function() {
			curr = $(this).find("img").attr("src");
			over = curr.replace(/_off\./, '_on.');
			$(this).find("img").attr({ src: over});
		},
		function() {
			$(this).find("img").attr({ src: curr});
		}
	)

	$(".roll").find("img").each(function(i) {
		temp = this.src;
		pre = temp.replace(/_off\./, '_on.');
		preload_image_object = new Image();
		preload_image_object.src = pre;
	});
});