<script type="text/javascript" language="javascript">
<!--
function cambiaImagenes()
{
document.getElementById('td1').style.backgroundIma ge = "Creek.jpg";
document.getElementById('td2').style.backgroundIma ge = "Landscape.jpg";
document.getElementById('td3').style.backgroundIma ge = "Autumn Leaves.jpg";
}
-->
</script>
</head>
<body>
<form name="form" id="form">
<table>
<tr>
<td style="cursor:pointer;" onclick="location.href='grupored.com.mx;'" id="td1" background="Autumn Leaves.jpg" width="500" height="300"></td>
<td style="cursor:pointer;" id="td2" background="Creek.jpg" width="500" height="500"></td>
<td style="cursor:pointer;" id="td3" background="Desert Landscape.jpg" width="500" height="500"></td>
</tr>
<tr>
<td colspan="3">
<input type="button" onclick="javascrip: cambiaImagenes();" value="Cambiar imagenes" />
</td>
</tr>
</table>
</form>
</body>
puedes intentar algo aso
saludos