function preload_images(images, pointer, callback) {
	if (images.length > pointer) {
		$('<img />').load(function() {
			preload_images(images, pointer + 1, callback);
		}).attr('src', images[pointer]);
	} else {
		callback();
	}
}

var lock = false;
$(function() {
	if (lock) return;
	lock = true;
});