function cacheImages()
{
    if (document.images)
    {
        img1 = new Image(256, 64);
        img1.src = "/i/img/button-information-hover-256x64.png";
        img2 = new Image(256, 64);
        img2.src = "/i/img/button-screenshots-hover-256x64.png";
        img3 = new Image(256, 64);
        img3.src = "/i/img/button-download-hover-256x64.png";
        img4 = new Image(256, 64);
        img4.src = "/i/img/button-purchase-hover-256x64.png";
    }
}