// Grab the array of images from the XML document.
        var xmlDoc = xmlhttpobject.responseXML;
        var ListItems = xmlDoc.getElementsByTagName("z:row")||xmlDoc.getElementsByTagNameNS("*","row");

        // Select a random item from the XMl.
        var SelectedItem = Math.floor(Math.random() * ListItems.length);

        // Compile the URL which we'll use for the image.
        PictureURL = "/" + ListItems[SelectedItem].getAttribute("ows_RequiredField");