Hi,
I'd like to make my gallery with 3 level of access... public (only some photo), friends (public photo + some more photo but not all) and private (all photo).
Is it possible to have this kind of access rights?

Thanks in advance

Please take a look here: http://www.zenphoto.org/2008/07/an-overview-of-zenphoto-users/

Thanks for this, but I already read it and didn't find the solution I was looking for.
Basically, within the same album I would like to have all pictures visible to me, some to my frieds (subset obviously) and a further subset visible without logging in.. I don't think that is possible, isn't it?

Well, the post acrylin flagged shows what zenphoto can do. So, if it is not what you want, then the answer is what you want is not possible.