I know there were some pictures of the carbon freeze chamber printed before the movie was out. Whether they were officially sanctioned I have no idea.

IIRC, there was mention in the Alan Arnold making of book about someone at the lab making stills from the dailies, and selling them to the press.

Empire was supposed to be a closed set with tight security. Somebody dropped the ball if Prowse walked in with an unknown woman on his arm and admitted her. Then again, Prowse is a pretty imposing fellow!

Was Han getting frozen actually leaked to the press?