c80e4651_Post_PHP_Photo_Gallery_Support__Description
[Option] Require users to be registered to view images? [Variable] reqregister [Description] 
If you want your users to be registered to view images, then set this value to YES. Users will still see thumbnails, but will have to register to see medium or large images. This is good for “closed” board where you want to minimze bandwidth usage by non-members.
PhotoPost PHP Photo Gallery Support
Description