Xiaomi
Hide an Album auf Xiaomi
By default, every album you create in the Gallery app stays visible in the main overview. There is no per-photo privacy setting, only a per-album one, so the whole folder needs to be hidden as a unit if you want its content out of sight.
To hide an album, open Gallery ➔ Albums, then press and hold the album you want to hide until a menu appears. Tap Hide and confirm with OK. The album is removed from the Albums tab immediately, but the photos and videos inside it stay untouched on your storage.
What actually happens
Hiding only affects how the Gallery app displays the album. The files are not moved, encrypted, or deleted, so other apps that scan your media storage can still list them. If you need a folder to be truly invisible to every app, moving it out of the shared media directories is a better option than hiding it in Gallery.
Finding hidden albums again
Hidden albums are not deleted from your phone, just filtered out of the default view. You can bring any of them back through the Gallery app settings whenever you need access again.