The wiki has a pretty good discussion of the issue, but note that the movie industry has a specific provision in the law deeming contributions to them to be work for hire (though this provision does require a written document).
The selfie argument is admittedly a stretch, but you might be able to argue that motion picture actors working on films are actually employees, given the unusual amount of control that the movie companies exert over their working conditions (when, where, for how long, what you do, how you do it, etc.) in a way that independent contractors aren’t normally subject to. Of course factors like how, when, and how much they are paid would cut in the opposite direction.
