.call { float: left; display: block; width: 265px; height: 166px; text-indent: -9999px; }
a.one { background: url(../images/call-interactive.png) no-repeat top left; }
a.one:hover { background-position: bottom left; }
a.two { background: url(../images/call-download.png) no-repeat top left; }
a.two:hover { background-position: bottom left; }