var imagenumber = 5 ; 
var randomnumber = Math.random() ; 
var rand1 = Math.round( (imagenumber-1) * randomnumber) + 1 ; 
images = new Array 
images[1] = "images/randimg/bild1.jpg" 
images[2] = "images/randimg/bild2.jpg" 
images[3] = "images/randimg/bild3.jpg"  
images[4] = "images/randimg/bild4.jpg"
images[5] = "images/randimg/bild5.jpg"  
var image = images[rand1]