The two settings
- Public — every link that opens the album sees it.
- Private — only links that grant it — “All galleries of the album”, or “Selected private galleries” with this one ticked.
Good to know
- Use private galleries to give different people different parts of one album — the family's portraits, the sponsor's set.
- Change it with the Public / Private pill in the gallery's header.
- A link to the whole library opens the public galleries; for private ones choose “Pick albums” and set what each album opens.
- Private galleries are part of the Pro plan and above.