Mine

.btnBase
{
	cursor: pointer;
	border:  none;
}

.btnDownload
{
	background: url(bilder/buttons/download_small_idle.png) center center;
	width: 66px;
	height: 18px;
}
.btnDownload.over
{
	background: url(bilder/buttons/download_small_over.png) center center;
}