var mess = new Array('<img src="images/image1.jpg">','<img src="images/image2.jpg"','<img src="images/image3.jpg"','<img src="images/image4.jpg"',
'<img src="images/image5.jpg"','<img src="images/image6.jpg"');
var max = mess.length;
var num = Math.floor((Math.random() * max));
document.writeln(mess[num]);