I have a situation. One of the models I have been shooting has suddenly caught the eye of the commercial world and has been in a national commercial for a large energy company (released last week) and is also on the third audition for a television series with a network. I have lots of photos of this person and I am being asked to shoot more. I do have model releases for each shoot and own the copyrights (stated in the releases and embedded in exif), but in this case should I register the photos with the U.S. copyright office? I just don't know when doing such a thing would be appropriate, but it seems this might be. Thanks!