if (document.images) {            // Active Images
            img1on = new Image();
            img1on.src = "/images/link_our_work2.gif";
            img2on = new Image();
            img2on.src = "/images/link_about_us2.gif";
            img3on = new Image();
            img3on.src = "/images/link_clients2.gif";
            img4on = new Image();
            img4on.src = "/images/link_contact2.gif";

            img1off = new Image();
            img1off.src = "/images/link_our_work1.gif";
            img2off = new Image();
            img2off.src = "/images/link_about_us1.gif";
            img3off = new Image();
            img3off.src = "/images/link_clients1.gif";
            img4off = new Image();
            img4off.src = "/images/link_contact1.gif";


        }

// Function to 'activate' images.
function imgOn(imgName) {
        if (document.images) {
            document[imgName].src = eval(imgName + "on.src");
        }
}

// Function to 'deactivate' images.
function imgOff(imgName) {
        if (document.images) {
            document[imgName].src = eval(imgName + "off.src");
        }
}