Depends a little bit on their location doesnt it?
Most countries have different copyright laws and there are substantial differences in how they are upholded.
Shortly: In Sweden a photo is protected from the taking to 70 years after the photographers death if the photo is seen as a work of art otherwise it is protected 70 years afters its taking. To "earn" this protection you do not have to copyright the photo neither publish your name on it, it is the copiers duty to investigate these things. It is legal to copy the photo without permission for private use, or our society's educational use or cultural use. Thus publishing a photo on a Swedish server without permission is eligible for legal action, I believe this is the case for most EU countries since Sweden changed its law in 94 due to a EU directive. I believe that in some EU-countries you still have to mark the photo as John does to "earn" this protection.