Every picdrop account has exactly one account owner. Team members can be added indefinitely.
The access rights for team members can be set individually: Explanation of the different access rights for team members
The account owner of the picdrop account, on the other hand, always has full, writing access to:
all galleries
the administration of team members
all details about billing and plans
Team members cannot get access to the administration of other team members or the billing details and plans.