I am building my gallery with ZenPhoto and I find that it is a really powerful tool.

I would like to set up the following feature to manage protected albums :
- have a page of connection for users which also allows the registration of the users
- when one user is not connected, [b]he does not see protected albums[/b] (at present we have an image with a bolt) in the list of the displayed albums.
- when one users is connected, [b]he can see and access the protected albums[/b]

how can i do that ?

Unpublished albums are not visible to users not logged on.

But are accessible by anyone who knows the url. I suggest to read the user guide entry about user rights.

sure, they're not visible ti users not logged on.
but they're in the liste of displayed albums, with a lock on the thumbnail.

i wish that the protected albums are not displayed at all, unless you are connected.

example :
you have 3 albums : 2 unprotected and 1 protected.
if you are not connected, you only see the 2 unprotected
if you are not connected, you see the 3 albums

You are getting "protected" and "published" confused, I think. If an album is unpublished, only logged-in users with access to that album can see it. It sounds as though you are wanting a combination of protected and published to accomplish what you want.

As said before, it would be a good idea to read the User Guide entry about this.