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(
    '/img/nav/bg-drop-down-t.png',
    '/img/nav/bg-drop-down-c.png',
    '/img/nav/bg-drop-down-b.png',
    '/img/nav/bg-dealer-drop-t.png',
    '/img/nav/bg-dealer-drop-c.png',
    '/img/nav/bg-dealer-drop-b.png'
);