I have just recently become involved in possible copyright complications. Fortunately I'm only slightly involved in supplying material for a project and the people I'm dealing with are fully aware of copyright restrictions. From what I have been told copyright restrictions last for 28 years plus a possible further 28 year extention. In this particular situation we are dealing with music copyright but I would imagine that photos are the same. I tried last year to get a photo from Archives Canada but was stymied by a family copyright on the photo. There is a form you should have signed by anyone who supplied with an image, to protect yourself from being sued.

http://dileas.mapleleafup.org/