International photo copyright rules?

[Seppo Sipilä]

Sorry if these are thoroughly answered questions - if so, please just
point me to the answers. I tried googling but it brings up such a
multitude of answers (which are conflicting of course) that it's hard
to find the truth.

I'm curious about copyright issues of old photos. There are heaps of
them on the web, and not many have clear copyright statements
attached.

1) Is there any international rule about photo copyright protection,
e.g. 50 years protection after the photo was produced or something
like that?

2) If there is no such rule, let's say that the national legislation
is more restricting in one country and someone there publishes on the
web a copyrighted photo (illegally if he hasn't asked for permission
and it's 55 years old while in that country the copyright protection
lasts 70 years, or legally if he has permission from the copyright
owner). If someone in another country with a 50-year protection rule
downloads and publishes it (on the web or in print), does he commit a
copyright violation?

Another thing are pictures in e.g. the Hulton-Getty Archive which seem
to be strictly copyrighted even if they are 100 years old (not works
of art, just plain newspaper photos). How does one extend the
copyright protection of such old photos, and is the extension valid
internationally?

Thanks in advance...
S.