Preload images with CSS

preload.css

#preloadedImages {
width: 0px;
height: 0px;
visibility:hidden;
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();
}