vBulletin has a feature that lets you make a forum and in order to see that forum you have to pay via paypal ( or some other pay place )
Does Gallery tap into this feature somehow so that one of my picture Cats. can become a pay only area?
With vB subscriptions, instead of moving the user to a new usergroup, you can also pick/choose certain forums that the subscription will give the user access to. You can't do this same type of thing with Gallery. You'll have to use usergroups to control what your paying/non-paying members have access to in the Gallery.