I want my gallery to be open for the general public to sign up and post photos.

I might want some security such as admin aproval of registrations but essentially the idea is as above.

I have found the plugins section in the admin area and enabled and configured register_user but I cannot find out how to access the registration page to test the website.

Since only "guests" need to register the link is not shown if you are already logged in. So log off and you will see the links.

The site has changed overnight, a cookie must have expired or something. I was able to log out from the admin console before but that would take you back to a mostly blank page. This morning when opening up the site it has loaded one of the themes I specified and there is a register button but it is tiny right at the bottom of the screen.