function setPic() {
    var picHold = document.getElementById("page-image");
    var pics = new Array("lucentum_banner1.jpg", "lucentum_banner2.jpg", "lucentum_banner3.jpg", "lucentum_banner4.jpg", "lucentum_banner5.jpg", "lucentum_banner6.jpg", "lucentum_banner7.jpg", "lucentum_banner8.jpg", "lucentum_banner9.jpg");
    var choose = Math.floor(Math.random() * pics.length);
    picHold.style.background = " url(" + '/images/' + pics[choose] + ") no-repeat";
}

function addLoadEvent(func) {
    var oldonload = window.onload;
    if (typeof window.onload != 'function') {
        window.onload = func;
    } else {
        window.onload = function() {
            oldonload();
            func();
        }
    }
}

addLoadEvent(setPic);