Me autorespondo:
<html><head>
<title>Tabla </title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<style type="text/css" media="screen">
td.marco {
height: 600px;
width: 1024px;
padding: 0px 50px;
border: 1px;
}
.banda {
width: 177px;
height: 700px;
verflow: auto;
background-image:url(fondotransparente.png)
}
</style>
<script language="JavaScript" type="text/javascript">
var image = new Array();
image[0] = 'random1.jpg' ;
image[1] = 'random2.jpg' ;
var index = Math.floor(Math.random() * image.length);
document.write('<style type="text/css"> td.marco { background-image: url('+ image[index] +') } </style>');
</script>
</head>
<body>
<table align="center" cellpadding="0" cellspacing="0">
<tr>
<td class='marco'><div class="banda"></div>
</td></tr>
</tr>
</table>
</body>
</html>