Hi! This is a demo page from Marcofolio.net.
This demo belongs to A parallax illusion with CSS: The Horse in Motion.
Resize your browser, changing only the width. While you resize, you'll be able to see an optical illusion. It'll seem as if the horse is running.
This technique also works on the cover of the book Magic Moving Images.
Go to the article and download the source to implement it on your website.
Uh oh! Looks like you are using Internet Explorer 6 or below. Only browsers than can display alpha transparent PNG's will see this effect in all it's glory