var imagenumber = 3 ; 
var randomnumber = Math.random() ; 
var rand1 = Math.round( (imagenumber-1) * randomnumber) + 1 ; 
images = new Array 
images[1] = "http://www.markus-kellermann.de/images/markus.jpg" 
images[2] = "http://www.markus-kellermann.de/images/markus2.jpg" 
images[3] = "http://www.markus-kellermann.de/images/markus3.jpg" 
var image = images[rand1]