Copyright is clear. You are breaking copyright law if you copy text or drawings within 70 years of the writer or artist's death. If the author/artist has been dead for 70 years and if you own the original publication or drawing then you have no problem. You do have a problem if you are copying a reproduction in a modern publication because the author of that publication has paid copyright dues for permission to reproduce the original and you are therefore in breach of the copyrigtt of the modern publication. Original document/ drawings etc are owned by indivuiduals and museums and they may grant you permission to photogroph them and reproduce. If you are copying someone else's photograph of an original then you are in breach of that photographer's copyright.
In Britain, we do have an understanding of fair copying which relates to a very small part of a document for educational or study purposes - that would be perfectly acceptable for a websitelike TMA. Copying the whole of a drawing is not allowed.
OK - you might get away with it, but the short answer is that it is THEFT.