// JavaScript Document

 MyImages=new Array();
    MyImages[0]='images/studentpics/hmpic1.jpg';
    MyImages[1]='images/studentpics/hmpic2.jpg';
    MyImages[2]='images/studentpics/hmpic3.jpg';
    MyImages[3]='images/studentpics/hmpic4.jpg';

    function newImage()
    {
        document.getElementById("mainImage").setAttribute("src", MyImages[Math.round(Math.random()*3)])
    }