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(
    '/images/checkbox.gif',
	'/images/check_x.gif', 
	'/images/login-bg-trans2.png'
);