Q: how can I see all albums a photo is in?

This function is not currently available in Photos. You can request Apple to add it via this link:

http://www.apple.com/feedback/

It is, however, possible to create a smart album that will include all images that are "not in any album."

Yes it's possible I believe using a script, I just don't know the script myself. Hopefully someone who does will pop along and advise, if they don't please repost the question.

Use this script - How to find out the albums a photo is in: Jacques Rioux's script

Or use the script compiled into an application by Old Toad - http://www.oldtoadstutorials.net/No.P01.html

LN