Yahoo's photo-sharing site, Flickr, has been an early and enthusiastic supporter of Creative Commons licenses. But there's one aspect of the licenses that Flickr doesn't respect: Users can remove the Creative Commons designation from their photos -- even though that may violate the terms of the license.
Creative Commons offers several licenses that people can attach to their creations as alternatives to more-restrictive copyright protection. Under CC licensing, content creators can indicate that their works are OK to republish under various specific conditions. Once applied to a creative work, Creative Commons licenses are supposed to be permanent
and this is the kicker:
Flickr provides more flexibility to photographers than Creative Commons does. On the popular photo-sharing site, users can switch photos back and forth -- without limitation -- between CC licenses and "all rights reserved" copyrights.
Read the full posting here to see what you can do to protect yourself if you have used a Creative Commons licensed picture that then changes its license.