/* image-rect */
div.test_image-rect {
	background-image: url(link.png);
	background-image: -moz-image-rect(url(link.png), 0, 32, 100%, 0);
	background-position: 50% 0;
	background-repeat: no-repeat;
	height: 26px;
	margin: 1.5em auto 0.5em;
	outline: 1px solid red;
	width: 96px;
}

div.test_image-rect:hover { background-image: -moz-image-rect(url(link.png), 0, 63, 100%, 32); }