MyImages=new Array();
    MyImages[0]='javascriptimages/1.jpg';
    MyImages[1]='javascriptimages/2.jpg';
    MyImages[2]='javascriptimages/3.jpg';   
    MyImages[3]='javascriptimages/4.jpg';
    MyImages[4]='javascriptimages/5.jpg';
    MyImages[5]='javascriptimages/6.jpg';  
    MyImages[6]='javascriptimages/7.jpg';
    MyImages[7]='javascriptimages/8.jpg';
    MyImages[8]='javascriptimages/9.jpg';   
    MyImages[9]='javascriptimages/10.jpg';
    MyImages[10]='javascriptimages/11.jpg';

    function newImage() 
    {
        document.getElementById("mainImage").setAttribute("src", MyImages[Math.round(Math.random()*10)])
    }