window.onload = setImages;
function setImages() {
    var holder = document.getElementById("prod_box_picture");
    var imgElements = holder.getElementsByTagName("img");
    var imgList = new Array();
    for (var i = 0; i < imgElements.length; i++) {
        imgList[i] = imgElements[i].src;
    }
    for (var i = 0; i < imgElements.length; i++) {
        var index = getRandom(imgList.length);
        imgElements[i].src = imgList[index];
        imgList.splice(index, 1);
    }
}

function getRandom(max) {
    return Math.ceil(max*Math.random()) -1;
}