Select iCloud in the Source list.

Select the shared photo stream whose subscribers you want to change, and click the Info button in the toolbar.

In the Subscribers section of the Info pane, do one of the following:

    To invite a new subscriber: Type the invitee’s email address.

    If the person you’re inviting doesn’t have an iCloud account, select the Public Website checkbox.

    To remove a subscriber: Select the subscriber’s email address, and press Delete.