to disable photo uploading and displaying for all members of the staff OWA policy. profile service permissions are found under the sharepoint admin center user profiles page then select manage user permissions. You can then allow or deny permissions to Create Personal Site (required for personal storage, newsfeed, and followed content) Follow People and Edit Profile , Use Tags and Notes. The profile policies page allows you to disable individual fields on their profile such as phone number, full name and all the other fields found on the edit profile page.
Set-OwaMailboxPolicy staff -DisplayPhotosEnabled $false -SetPhotoEnabled $false