<html>
<head>
<script type='text/javascript'><!--
function cellImg(idCell, imgName) {
document.getElementById(idCell).style.background = "url(" + imgName + ")";
}
//--></script>
</head>
<body>
<table width="50%" height="50%" border="1">
<tr>
<td id='c1'>
<a href="javascript:cellImg('c1','red.gif')">c1</a>
</td>
<td id='c2'>
<a href="javascript:cellImg('c2','blue.gif')">c2</a>
</td>
</tr>
</table>
</body>
</html>