"facebook_admins" allows you to add "fb:" tags to mark some Facebook users/pages/applications as the admins of your gallery, mainly used to access Facebook Insights and Comments.
This module may be downloaded from the GalleryModules here.
To install, extract the "facebook_admins" folder from the zip file into your Gallery 3 modules folder.
Afterwards log into your Gallery web site as an administrator and activate the module in the Admin -> Modules menu.
Configure the module: Settings -> Facebook_admins page. You will be able to edit attributes of the module. Save