Why can't I move photos to Photo albums without creating duplicates?

Hidden pictures are not moved-- they are just marked "hidden," and wherever they are normally seen they don't show-- but they are just as "there" as they were before. And the Library continues to own that picture, even though it doesn't show it.

In Photos, pictures aren't exactly "in" an album. When you "put a picture into an album," its name is added to a list of pictures from the Library that 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 (like two playlists with the same song,)  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. You don't get fewer pictures in your Library because you remove one from an album; you just get fewer names in the album list.

So albums give a specific view of your pictures. The picture of "Aunt Ethel at the Grand Canyon" can be in the "Aunt Ethel" album with other pictures of Aunt Ethel, and it can also be in the "Grand Canyon"  album with pictures of other people at the Grand Canyon. And it can also be in a the "September 2015" album with other things that happened then. Each album is pointing to a single file stored in the Photos Library, so having pictures in multiple albums takes up no more storage space. As you can imagine, this is very powerful in organizing pictures. Your pictures aren't confined to one album, and there are no duplicates made to put into extra albums.

Marking a picture as "hidden" just lets albums know not to show that picture, but it remains on the list. The Hidden "album" just shows all the pictures in the Library that have a "hidden' mark.

Bill0827 wrote:

Actually, that is not the case I’m talking about moving them not creating duplicates. You could put an actual album in where you could move your photos to the albums. You wouldn’t put a Led Zeppelin song in your family photo album now with you? Unless it related to the family, that’s what I mean by organization Not having everything cluttered into one.

Your photos are not being duplicated when you put them in an album. They are just a link to the original photo in your library. You use the albums to organize your library any way you wish and there is no restriction on having the same photo in multiple albums without having it take up additional storage space by having it duplicated. You also don't need to worry about losing any photos when you delete an Album.

It also makes checking for duplicates work correctly as the duplicate should only report a duplicate if there is more than one photo in your Library. If they were reported as duplicates when used in different albums, then deleting duplicates would remove the photo from every album, but one. Thankfully that is not the way it works.

The analogy for Music is the same where you may want the same song in multiple playlists. It would be incredibly inefficient if that required the song to be duplicated in each playlist. That is the purpose of having a Library and why it is consistent using both apps. You surely would not want deleting a playlist to remove every song you have there from your Library.

it seems to me that while each photo is a file in Finder, in Photos a picture (except for the unmodified original) is not a file, but rather it's an image that may be represented by lots of files-- a thumbnail file, the preview file, cache files, and the database files themselves--as well as several others. That's the thing-- in Finder the picture is treated as a file; in Photos the picture is treated as an image.

Exactly. I've debated this many times here over the years and the best I can come up with is as follows:

A jpeg is not your photograph, in the same way as the word file is not your novel. These things are containers, shoe boxes basically, which are (to lesser or greater degree) optimised to accommodate the particular kind of shoe within. You can organise your warehouse by the shoeboxes but is that really useful when you're looking for a particular style and size of shoe? Surely it is better to arrange your warehouse with reference to the contents of the boxes and not the boxes. The Finder is all about the boxes. It doesn't care if that file is a text one, or an image one, or video. It's just a file to the Finder. So the potential to find data within a file is limited. In Photos (and Music) the arrangement is by the data within the file, not the file. It's what a database is and does.

An album is Photos is not a place. It's a list. A command to tell the app to display this bunch of images together. If you don't want that then the solution is not to hope Apple are going to change their basic philosophy on this after more than 20 years. The solution is to use an app that works the way you prefer.

Bill0827 wrote: …that’s the way it should be done. … that’s the whole point that’s organizing your photos.

Actually, what you are suggesting would really limit the ability to organize pictures. It would be like having songs in your music list being duplicated for every playlist, wasting tons of storage. Having each picture file in only one album would be the same as having each song in only one playlist. People with lots of pictures really need the flexibility that that a database system provides.

You could put an actual album in where you could move your photos to the albums.

So you think of photographs and albums like files and folders, and if you want to do that then don't use Photos, just use the Finder. Each photo is a file. Each album is a folder. But that's missing the point of a database - which is what Photos is. It allows you to manipulate the data and not the file. Photos is about the content - the photograph and associated metadata - and that allows you to do things like non-destructive editing, smart albums, searching and organisation based on Exif and IPTC metadata - even very simple things like having the same photograph in multiple albums. And in the library nothing is cluttered. It's just all your images stored on date and time. I guess the one downside of a database is you have to follow a short learning curve.

Albums are virtual elements of a Photos library. They are not actual entities but a database item that photos dragged to it are listed and shown as Richard pointed out. That's how all DAM (Digital Asset Management) apps work. That way you can have the same picture in multiple albums and projects and have only one image file for that photo in the library. A real space saver. And the app is free.

Bill0827 wrote:

I get all of that. I already read that. If Apple really wants some versatility, that’s the way it should be done. When you move a photo to an album it shouldn’t just create another image of it. It should allow you to move it to the album that’s the whole point that’s organizing your photos. I don’t want my main Library cluttered up with everything. So I hope someone from Apple read this

Don't hope: tell them.

Feedback - Photos - Apple

But do explain when you do how exactly you think that library that shows some but not all images should work.

I did not follow that. I have actual albums. I used examples of Aunt Ethel at the Grand Canyon.

The Library shows all the pictures in your Library. Seems reasonable. You have the option of not using it if you don't like it.

On a Mac we can use a Smart Album to show all the pictures not in an Album, among many other things. Unfortunately Smart Albums aren't available on iOS or iPadOS. Pretty much everyone wishes they were. If that's what you need, then please follow Yer_Man's suggestion of giving Apple feedback, and request Smart Albums. I have.

I certainly agree with all that. But I've been thinking about this:

Yer_Man wrote: Each photo is a file.

and it seems to me that while each photo is a file in Finder, in Photos a picture (except for the unmodified original) is not a file, but rather it's an image that may be represented by lots of files-- a thumbnail file, the preview file, cache files, and the database files themselves--as well as several others. That's the thing-- in Finder the picture is treated as a file; in Photos the picture is treated as an image.