Alright, thanks!
In the build game settings though (that's the first place I went), I don't see the option to
add an image, just to change the existing ones (like to swap the existing images for different ones). I want to keep everything the same, just add another image. I guess it'd be considered an overlay?
There would be a point to adding normal maps though. It'd let you have refractive effects on the screen. The different glass effects you normally get in-game are really just transparent normal maps. Oh well, maybe a future update.
And I did search. All I got was stuff on how to
change stuff, not add it. I want everything the same, just with the image I made. I even checked Plystire's tutorial in Nickydude's Guide, it only said how to move stuff around and change the pictures, nothing about adding stuff.
Settle for nothing but the best.