Hax,
I have done some testing myself and this is what I have found.
Install 3.3.1 (single site, fresh install), after the image store plugin is activated the default user role is set to ‘customer’.
Registrations work from the back end in both the Image Store ‘New Customer’ and the ‘Add user’ functions. That is the user is registered as a customer and the user appears in the Customers list in Image store.
However, if the user registers them self through the wordpress registration/login window, the user is assign the customer role but their details do not appear in the Customers list in Image store.
User registration via the WP-CRM plugin both in front and back end registrations. ( This last note more of FYI, thoough it would great if the plugins worked together.)
Alos, the Customer tab in the Edit Gallery window doesn’t pick up the customer list. Is it meant to?
I hope this helps!