var preloaded = new Array();
function preload_images() {
    for (var i = 0; i < arguments.length; i++){
        preloaded[i] = document.createElement('img');
        preloaded[i].setAttribute('src',arguments[i]);
    };
};
preload_images(
    '/gfx/logo_rf_rollover.png',
    '/gfx/logo_1_z.jpg',
    '/gfx/logo_2_z.jpg',
    '/gfx/logo_3_z.jpg',
    '/gfx/logo_4_z.jpg'
);