Yes, it is possible that it is a breach of copyright - it depends on context, of course - permission may have been granted by the the owner to copy it and to put it on PG!

The original photographer (or possibly employer) holds copyright until 70 years after their death. This requires that the picture is credited in the first place - otherwise you are expected to do everything in your power to find out who the copyright holder is.

If it is in a book, then the book author may be the copyright holder, assuming he had permission to use it in the first place - otherwise, he may be in breach.

It is complicated!