In an album's Properties I change the setting "Album can be viewed by" from "Me only" to "Everybody (Public Album)", and click the Update Album button. However, the system comes back with "No update needed", and the change isn't saved. What am I doing wrong?
You set an album password. If you did, the setting will always remain to me-only. That's how the script works. Read up http://coppermine-gallery.net/demo/cpg14x/docs/index.htm#album_prop
From that section of the docs:
QuoteNote: when setting an album password, the permission dropdown field "Album can be viewed by" will be switched automatically to "me only" - this is expected behaviour. If you change the "Album can be viewed by" to another selection, you must disable the album password as well.
Aha! Many thanks Joachim.