var mess = new Array(
'<img align="absmiddle" src="images/image1.jpg" width="265" height="131">',
'<img align="absmiddle" src="images/image2.jpg" width="265" height="131">',
'<img align="absmiddle" src="images/image4.jpg" width="265" height="131">',
'<img align="absmiddle" src="images/image5.jpg" width="265" height="131">',
'<img align="absmiddle" src="images/image7.jpg" width="265" height="131">');
var max = mess.length;
var num = Math.floor((Math.random() * max));
document.writeln(mess[num]);