
There is an ongoing controversy (involving Hollywood and copyright? I know, improbable!) about the use of frame enlargements versus studio-photographed stills which, as we all know, are sometimes very different from the scenes they're supposed to portray. Exactly who owns what, or has the rights to what, or whose job it is to obtain the rights, is as clear as mud. There's a paper about it at http://c.ymcdn.com/sites/www.cmstudies.org/resource/resmgr/docs/fairusefilmstills.pdf.
Having read into the subject, all I can say is that it's every bit as complicated as everyone says, and way, way more.