1. What code do I have to add to my themes image.php to display IPTCCity, IPTCImageCredit and IPTCcopyright?
   similar to:

2. When I edit my albums, I can enter content to a field "Location".

What code do I have to use on my themes album.php to display this field "Location"?

3. How to add more fields (like Location) to Albums?

e.g. City, Copyright

I guess that could be done via filters in a plugin...

Thanks`

You should probably be familiar with the Zenphoto themeing tutorial and object model at this point.

Then take a look at the create_album plugin ( http://www.zenphoto.org/news/create_album ) for an example