Coppermine photo gallery is an easy-to-use gallery script. It supports multiple languages and is suitable for any kind of online albums. You can find many free to use Coppermine themes and thus customize the outlook of your gallery.
Coppermine stores the images in albums, which can be grouped in separate categories. It also supports multiple users and the administrator of the gallery can determine the access level to the script features for each one of them. The administrator can also define the allowed actions for the unregistered users.