Zoinks points to a story about Microsoft's new 'Windows Media Photo' Format. It's touted as a superior alternative to JPEG and certainly there's nothing bad about improved technology in image formats.
I guess everyone will question what restrictions might exist with a Microsoft-owned format versus an open source format licensed under GNU (or something equivalent). On the other hand, if Microsoft's Internet Explorer adopts support for the format quickly, it's probably that (unless Microsoft actions preclude it) other browsers will adopt support for it too.
More details at Microsoft's site for the format.