var mess = new Array
('<img src="images/a.gif" alt="number" width="200" height="40">',
 '<img src="images/b.gif" alt="number" width="200" height="40">',
 '<img src="images/c.gif" alt="number" width="200" height="40">',
 '<img src="images/d.gif" alt="number" width="200" height="40">',
 '<img src="images/e.gif" alt="number" width="200" height="40">',
 '<img src="images/f.gif" alt="number" width="200" height="40">',
 '<img src="images/g.gif" alt="number" width="200" height="40">',
 '<img src="images/h.gif" alt="number" width="200" height="40">',
 '<img src="images/i.gif" alt="number" width="200" height="40">',
 '<img src="images/j.gif" alt="number" width="200" height="40">'
);
var max = mess.length;
var num = Math.floor((Math.random() * max));
document.writeln(mess[num]);