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_teplo/head-kond-over.gif',
    '/images_teplo/head-tower-over.gif'
);