CSS 实现图片预加载

#preloadedImages {
       width: 0px;
       height: 0px;
       display: inline;
       background-image: url(path/to/image1.png);
       background-image: url(path/to/image2.png);
       background-image: url(path/to/image3.png);
       background-image: url(path/to/image4.png);
       background-image: url();
}