Everything works right, and I have been spending weeks putting finishing touches on the gallery, and then I find it doesn't display anymore than 5 galleries on the index or archive page.
Frustrating to say the least.
I tried to tinker with the code but that doesn't do anything. Is it a CSS problem?
Why does it stop listing galleries at 5?

Well, first of all the default installation of Stopdesign has an "archive page", in which the front page only shows a certain number of albums, and then the archive page is designed to show the whole gallery set of pages.

If you look at this code snippet:

  Recently Updated Galleries

[list]

[*]
" title="View album: " class="img">
" title="View album: ">
[i][/i]

  [/list]
    View all Galleries

You notice that Stopdesign uses a counter on the front page to only show the first 6 albums. Now if your zp_config is set to default 5 albums, your display will only show 5 albums.

You can modify the number of albums per page by modifying the zp_config file. Mine is set to six, which I've found for most themes works well. Stopdesign works best set to 6. My Thinkdreams theme is a derivation of Stopdesign.

// Paging options:
// Control of their display is done in the theme, so you might need to change these
// after switching themes to make it look better.
$conf['albums_per_page'] = 6;
$conf['images_per_page'] = 6;

That did the trick.
Thanks very much, I appreciate it!

Where if the zp_config file? I can't find it.

That file has been renamed to zenphoto.cfg.
/zp-data/zenphoto.cfg

Some reading: http://www.zenphoto.org/news/installation-and-upgrading.

Why did you post in a 5 year old thread ?

Please also note that the information in this thread is hoplessly out of date. All these kinds of configuration changes are made on the "admin" pages via option settings.