All that's old is new again. A company called Forgent holds patent no. 4,698,672, which it claims covers JPEG images. They recently extracted a licensing deal from RIM, now claiming that they have earned over $100M in royalties for this patent. A lawsuit filed by Forgent against about 40 PC companies including Apple Computer, Dell, Hewlett-Packard and IBM is currently under way. They claim that about 1000 other companies also infringe their patent. Microsoft has filed for a declaratory judgement against Forgent, seeking to invalidate the patent.
So, the Internet's two most popular image formats, GIF and JPEG, are unsafe. That leaves PNG as the only somewhat-widely supported format to fall back on if you want to avoid patent encumberence. How long until a company finds a long-forgotten patent that covers some idea embodied in PNG, and decides to submarine that as well?