For some time you could see pictures someone sent you via Hangouts in an album called "Hangouts". This vanished somehow.
When you open a picture from Hangouts on the Computer, you can still see in the URL that there is some kind of album. The URL is in the form https://plus.google.com/u/0/photos/albums/XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
and you can even browse this album.
How can I get to this album from Google Plus or Google Photos?