Any idea where, if anywhere the in-game (not Galaxy) screenshots are getting saved? They're not in any of the ordinary places I looked, nor where the INI file implied they would be.
Have you checked under the games' location in the GOG Games folder? There might be a special section for it there
Yep, that's where the INI file implied they'd be under A Hat in Time\HatinTimeGame\ScreenShots but no dice. I even tried making the folder to see if it would help. Before the question comes up, this is on a separate drive without UAC issues. And the paths in the INI file are relative, not absolute. So unless the game doesn't recognise relative paths... Thanks for the answer too.
From looking around various sources, I conclude that this is probably a bug in the GOG version as I saw no other place mentioning anything about photo mode or where the files end up (except 1 post on steam forums regarding this from a GOG user). I'm assuming the game uses Steams built in screenshot function when you take a photo, hence it does nothing on the GOG version.
I think you're right about it being a bug, but I don't personally think it's Steam-related. Of course I can't prove that, but them having a specific INI path for screenshots kind of points that way.