Refreshed, slimmed down design
I've created an updated set of mockups, which are intended to provide guidance for future Photos development. These can be seen here:
https://gitlab.gnome.org/Teams/Design/app-mockups/-/blob/master/photos/photos-mvp.png
The main goals are to reduce the overall featureset and improve the quality of what remains, with a focus on being a nice viewer and organiser for a local set of photos. Editing is not covered at the moment, but could be included if necessary.