One of twitter's largest image sharing services twitpic has just overhauled their terms of service, and signed a deal with celebrity photo agency WENN that allows them to sell on your images.
Not only do they have "a worldwide, non-exclusive, royalty-free, sublicenseable and transferable license to use, reproduce, distribute, prepare derivative works of, display, and perform the Content,". They can also hold onto your images even after they are deleted, until a "commerically reasonable" time has passed.
So whenever an image by or of a celebrity is posted to Twitpic and someone wants to use it, they pay out to WENN and Twitpic, not the original photographer.
At the moment the only twitter image service that leaves you with total rights to your images is Moby Picture
