as far as older postcards, many of the copyrights are not valid anymore, so it is not an issue on either end - and for those that are still under copyright, there is a disclaimer. the issue is either bandwidth usage (*theft*) or just being polite and crediting a source that has originally posted the image for folks to see. also, while having things like photos on file at the copyright office is nice, it is not required. it is only helpful during litigation. www.copyright.gov: In general, registration is voluntary. Copyright exists from the moment the work is created. You will have to register, however, if you wish to bring a lawsuit for infringement of a U.S. work