var x = new Array("images/head01.jpg","images/head02.jpg","images/head03.jpg","images/head01.jpg","images/head02.jpg","images/head03.jpg","images/head01.jpg","images/head02.jpg","images/head03.jpg");

var zaehler = x.length;

var zufall = Math.round(Math.random()*zaehler);
zufall = zufall - 1
if(zufall < 0) zufall = 0;