If you would like to give special permissions to Hide or Download images to a group of addresses at one time you can follow these steps:
From the Main Menu click on Photos > Galleries.
Locate your gallery and click on Visitors > Manage Visitor Emails.
Put a check mark in the box to the left of each email address you want to give permissions to.
Scroll to the bottom and click on Select an Action > Manage Visitor Permissions.
Choose from each of the items you want to allow permissions for and click Save.