preloading images in CSS

/* Preload images */
body:after {
content: url(../img/lightbox/close.png) url(../img/lightbox/loading.gif) url(../img/lightbox/prev.png) url(../img/lightbox/next.png);
display: none;
}

Does the above code really pre-load images ?? REALLY ??

Nice teachnique , found it in the CSS files of lightbox HERE