I have been playing a bit and produced a theme that lets me create a "Super Gallery".
http://testalbum-2.sbillard.org/zenphoto/
This is an example of creating a "Super Gallery". It is based on the 'Default' theme.
A "Super Gallery" is a gallery of galleries. You ask "Why would I want a "Super Gallery", Zenphoto does such a wonderful job of albums and subalbums, what could be the benefit of a Super Gallery?"
With a Super Gallery, each gallery referenced from the index page is a fully functional Zenphoto gallery. This means it can have its own album folder (naturally) but it also means it can have its own theme as well. So, you can have mixed themes in a Super Gallery. Separate galleries also means the possibility of separate administration. Each gallery can have its own admin user and password. This lets you assign a gallery to an individual to populate and maintain, but still keep the gallery "in the familly."
Creating a Super Gallery is almost as easy as creating a Zenphoto gallery. (Creating Zenphoto galleries is a supset of creating a Super Gallery.)
and at step 3? what is the theme I should select? I looked in the themes page...
This should be implemented as the zenphoto demo gallery so you can have a look and feel of all the themes instead of just the look on the themes page...