If you remove a user from a circle, their photos/videos will be removed as well. Each user is the copyright owner of their content.
PhotoCircle Premium Plans
PhotoCircle's Premium Plans require users to agree that their content belongs to the Workspace as part of the sign up process. For this reason, if you deactivate a user's account, their photo/video contributions will remain.
Upgrade to an Education & Nonprofit Premium Plan
Upgrade to a Teams & Business Premium Plan