To see the images, try the page ImgPreload1.html.
If you have access to the server, you will want to check out its access log. The server's log should show GET requests for some GIF files, though you don't see the images here. If you reload this page, the server's log should show the GET for this page, but not for the image files, because they are already loaded and should be in your browser's cache.
Feel free to copy this demo for your own uses. You will want to replace the images with your own, of course. The second page is probably of little value to you, so copy it only if you want your own version of this entire demo.