function doRollover() {
	$(".rollover").hover(function() {
			curr = $(this).attr("src");
			overlen = curr.length;
			over = curr.substr(0, overlen - 7);
			over = over + 'On.gif';
			$(this).attr({src: over});
		},
		function() {
			$(this).attr({src: curr});
		}
	)
	
	$(".rollover").find("img").each(function(i) {
		temp = this.src;
		prelen = temp.length;
		pre = temp.substr(0, prelen - 7);
		pre = pre + 'On.gif';
		preload_image_object = new Image();
		preload_image_object.src = pre;
	});
}