Purtroppo non l'ho testato ma prova a vedere se può andare.
Codice PHP:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<title>Prova</title>
<meta http-equiv="content-type" content="text/html; charset=utf-8" />
<style type="text/css">
#zoom
{
position: absolute;
top: 20px;
left: 20px;
}
</style>
</head>
<body>
<div>
[img]foto.jpg[/img]
<div id="zoom">[img]zoom.png[/img]</div>
</div>
</body>
</html>