copiato in giro ( www.google.it )
funziona con immagine down.gif e up.gif
	codice:
	<head>
<SCRIPT LANGUAGE="JavaScript">
<!--
theimage = new Preload();
function Preload(up, dn)
{
	this.up = new Image();
	this.up.src = up;
	this.dn = new Image();
	this.dn.src = dn;
}
function up(pointer)
{
	image = document[pointer]
	name = image.name;
	document[name].src = theimage[name].up.src;
}
function dn(pointer)
{
	image = document[pointer]
	name = image.name;
	document[name].src = theimage[name].dn.src;
}
theimage['AAC'] = new Preload("up.gif", "down.gif");
// -->
</SCRIPT>
</HEAD>
<BODY>
[img]up.gif[/img]</a>
</BODY>
 
 