Nice mouseover reveal

[Brocberry]

http://www.telegraph.co.uk/sport/oly...one-Roses.html

This will be javascript I guess?

Just thought I'd share

[Markdidj]

At a guess it's two areas with overflow:hidden, their sizes change depending on mouse position. Actually, only one size needs to change, the one with the lower z-Index can be static

With new browsers you probably could do this with just two background images and changing the css with the change of mouse position

[Logic Ali]

All that needs to be is two overlaid images, with a mousemove handler setting the CSS 'clip' of the upper image.