function newImage(arg) {
    if (document.images) {
        rslt = new Image();
        rslt.src = arg;
        return rslt;
    }
}

function changeImagesArray(array) {
    if (document.images && (preloadFlag == true)) {
        for (var i = 0; i < array.length; i += 2) {
            document[array[i]].src = array[i + 1];
        }
    }
}

function changeImages() {
    changeImagesArray(changeImages.arguments);
}

function toggleImages() {
    for (var i = 0; i < toggleImages.arguments.length; i += 2) {
        if (selected == toggleImages.arguments[i]) changeImagesArray(toggleImages.arguments[i + 1]);
    }
}

var selected = '';
var preloadFlag = false;
function preloadImages() {
    if (document.images) {
        praise_over = newImage("images/Inc-printing-customers-over.png");
        dig_over = newImage("images/menu-digital-printing-over.jpg");
        req_over = newImage("images/request-a-quote-over.png");
        off_over = newImage("images/menu-offset-printing-over.jpg");
        post_over = newImage("images/menu-posters-over.png");
        menu_over = newImage("images/menu-offset-printing-over.png");
        cop_over = newImage("images/menu-copies-over.png");
        grap_over = newImage("images/menu-graphics-over.png");
        gic_over = newImage("images/menu-giclee-over.png");
      preloadFlag = true;
    }
}