ВНИМАНИЕ!!!!

<script language="JavaScript">  
<!--  
var a=Math.round(Math.random()*2)  
image = new Array();  
image[0]="image.gif"  
image[1]="image1.gif"  
image[2]="image2.gif"  
document.write ("<img src="+image[a]+">");  
//-->  
</script>