This extension scopes galleries to sites. Spanners fork of multi-site is needed and does most of the work in the model (by putting a scope around find, essentially), so there are no controller modifications required.
- Gallery Extension
- Multisite Extension (Spanners fork)
You'll need to add ':gallery_observer' to the active record observers in your environment.rb connfig.
config.active_record.observers = [:user_action_observer, :gallery_observer]