Yuck. Every time my system has some random binary that doesn’t seem to resolve to any expected location it’s because it’s installed with flatpak, snap or appimage (why 3?!).
What percentage of people install this on their own computers?
Docker is much less manageable locally than, say, systemd or supervisor.
The only thing (which is something) that docker has going for it is that it's cross platform. But the same argument can be made for writing apps using electron. If you're going to do that, fine, but acknowledge the compromise. It's not better.
If portability is a project goal, maybe pick a language that is actually portable (which python is not). This is almost exactly the argument for Electron: I want a portable app written in js + html, therefore I need to include a js runtime (i.e. chromium + node) with it.
General question: does this have import from google photos? Please don't make me go through the google takeout pain.