From my understanding as long as you do not remove a studio mark, make money from posting the photo, or claim it as your own you will not be breaking copyright. But I would still use caution with more recent photos like the other replies have said. Also as for privacy issues, if the photos are not personal private photos then there should be no real objections from anyone, especially if everyone in the photo is deceased. And the worst that could happen really is that someone asks you to take them down.