Either? It supports various kinds of authentication. Could use OIDC (though that would require someone to also host an OpenID server and/or use commercial providers like google, probably wouldn’t go down super well with this community) or username/password. I’ll do some research and see if there’s a better option for a semi-public sharing system since Immich is primarily for semi-private use (you have to join the instance to upload things). Some kind of moderation approval would probably be critical to keep illegal content off, at a minimum. There are a lot of options!