<html>
<head>
<script type="text/javascript">
<!--
image01= new Image()
image01.src="tomcat.gif"
image02= new Image()
image02.src="bluetile.gif"
//-->
</script>
</head>

<body>
<a href="whatever.htm" onmouseover=
"document.images['example'].src=image02.src" onmouseout=
"document.images['example'].src=image01.src">
<img src="tomcat.gif" name="example"></a>
</body>

</html>