I have disabled our installation of gallery2, as I hinted to before. We have changed to use flickr and facebook to share photos with our friends and family. The main reason that I disabled it was because all of our photos, that we decided to share, were publicly available. gallery2 does support user authentication, but it is hard to have family create accounts on the site.
Since most people that we are sharing photos with have flickr or facebook accounts, that was a hurdle that we didn't have to go over to allow us to restrict access to our photos.