@charset "ISO-8859-1";
preload {      
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();   
}