When pressing s, each time the message pops up in the top left, but no image is actually saved (this screenshot was taken through printscreen). The reason it won’t save is because the file path contains “á” in the name -- once moved to a place where á isn’t in the filepath, it works fine. This happened on a Windows 10 64 bit PC, Renpy version 6.99.12.4.2187.
This is a minor gripe, but I feel bad for players who think they're taking screenshots throughout the game only to find out that they didn't save. If this is annoying to fix, maybe just an error message saying it didn't save?