$(window).load(function() {
	// set up rollover effect for the appropriate images
	$(".rollover").each(function(index) {
		var initSrc = $(this).attr("src");
		var dotPos = initSrc.lastIndexOf('.');
		var newPath = initSrc.substring(0, dotPos) + "_roll" + initSrc.substring(dotPos);
		$(this).attr("initsrc", initSrc).attr("rolloversrc", newPath);
		$(this).mouseover(function() {
			$(this).attr("src", $(this).attr("rolloversrc"));
		})
		$(this).mouseout(function() {
			$(this).attr("src", $(this).attr("initsrc"));
		})
		// preload the rollover image
		var image = new Image();
		image.src = newPath;
	})
})