In which album is this Photo?

Oppps!! Didn't see the other posts when I made this one and posted.

If a photo is in mujltiple albums it's the same image file. When a photo is added to an album all that's added is a pointer back to the original photo file.

If you want to know what albums a photo is in use this user created AppleScript: How to find out the albums a photo is in: Jacques Rioux's Script, Catalina Version for Photos 5 - Apple Community

It will show you what albums a photo is in. The script, compiled as an application, can be downloaded from this tutorial site:  P01 - Applescripts from Photos’ User Tips Compiled as Applications  

I use the album names as keywords. If I have an album named Circus Photos, I select all in that album and add the keyword "Circus Photos." If some of those pictures are in an album called Clowns, I select all in Clowns and add the keyword "Clowns." When I look at a photo I can tell which albums they are in with get info.

I do wish Photos had a category to do this, but keywords is a very powerful workaround. I actually use _Clowns, etc, so albums will show up first in the keyword list.

For the standard albums you can run an Apple Script to list all albums a photo is in (How to find out the albums a photo is in: Jacques Rioux's Script, Mojave version 2019), but there no way to test smart albums with Apple Script. You will have to look at the constraints for a smart album, to see, if it will contain a certain photo.

JaapKoole wrote:

A Photo can be in multiple albums, but in what albums is it?

You can add a photo to many albums, but the photos are not in the albums. Albums are not storing the photos. They are just referencing the photos. There is no distinguished album were the photos are saved. All photos are stored once in the library, and you can see it there by ctrl-clicking the photo and using "Show in All Photos".

Correct. Did you have a question?

This is the question you've answered in your first post, no?