Expanding on what stedman1 said, a picture that you can see in, say the Library view and also in 2 albums doesn't take up any more storage space than if it were in no albums at all.
Pictures aren't exactly "in" an album. When you put a picture into an album, its name is added to a list of pictures to display together when the album is clicked, kind of like a music playlist, but for pictures. So two albums can both have the same picture name in their lists, and that picture will show up when you click either album, but there's only one picture file-- it's just on multiple lists. And when you remove a picture from an album, its name remains in the lists of other albums, and the file still remains in your Library.
Library and Recents are are special pre-set ways to view your pictures. The "LIbrary" view shows all the pictures in your Library in the order your pictures were taken. The "Recents" view shows all the pictures in your Library in the order they were added to the Library-- not necessarily in the order they were taken. This can't be changed. These albums always provide the same view so that, when something goes wrong or seems off, you (and we) can depend on them always showing the same thing, and there's no chance that someone snuck in and changed the order or removed pictures.
