Can you delete photos in an album and keep them in your camera roll?

I'm trying to delete some photos so that I can get enough storage for my iPhone. And I'm really confused about how this thing works.
If some photos are put into albums, are they being copied? So if you delete photos in an album, only those in the album are deleted and the "original" photos in camera roll are still there? Is it safe to delete albums(or photos in albums) if I want the originals still exist in the camera roll?
and one more thing, does deleting photos in albums help you manage storage?

Yes