Dear Julia: I'm reasonably sure that the suggestion made by the Chinese studies librarian is based on a faulty understanding of copyright laws. If you want to be sure that you're not infringing upon any person's rights existing under the current copyright laws of the PRC, you should think about obtaining the advice of a lawyer who is fully familiar with those laws.
I have three questions about images relating to the 1950s-70s. Any advice would be much appreciated. Online or offline replies are fine.