Who can delete my photos in a shared Google Photos album?

Question

I recently shared some photos of an event with a shared Google Photos album. I had "Notifications" and "Collaborate" turned on in the album options. Several people joined the album and one person left a comment. I was not notified of any of this. Then a few days later when I looked at the album again, all but three of the photos were gone. I found them in the Photo App recycle bin. I imagined that I must have accidentally deleted them myself. I restored them back and checked the album. All was well. Until this evening when I checked and this time again, someone deleted the bulk of my photos and there were just a few left in the album. I could rescue the photos from the bin again, but have now switched off all collaboration and access to the album.

I was under the impression that album participants can only add or remove their own photos. So, how is it possible for this to have happened?

1. My account is compromised and someone is acting with my credentials.
2. People can object against photos in my album and ask Google to delete my photos and they do this without my consent / knowledge
3. I misunderstand Google Photos permissions

Answer 1

Sharing

Google Photos does allow anyone with access to a shared album to add others. If you have notifications turned on, Photos states in their documentation and app that they will notify you when new people are added. see → Share an album with specific people

  I performed a test and, like you, I was not notified when another user added someone to the shared album (not by email, not in the app, nor otherwise). I could of course see their account in the list of Album, members. I also did not receive a notification (email or otherwise) later when the newly added user left the shared album. Not sure what this means but clearly that cannot be relied on.

Trashing & Removing Photos

The photo deletion behavior you are describing does not reflect the functionality of Google Photos Shared Albums.

1. Google Photos does not have a "Recycle Bin", instead it has Trash or Bin, depending on your locale.
   
    

2. Remove Photo from a Shared Album
   To Remove a photo from a Shared Album you must be the photo or album Owner:

   	Album Owner	Not Album Owner
   Photo Owner
   Not Photo Owner		❌

    ^{Removal does not delete the source image or affect other albums.}
    

3. Move Photo to Trash
   Only the Owner of a photo can move it to Trash.

   	Album Owner	Not Album Owner
   Photo Owner
   Not Photo Owner	❌	❌

    ^{Photos in trash are also removed from albums.}