May I use sub-folders inside my game's folder or must all files like pictures and music be at the main folder?
How the game files must be organized if I plan emailing the game to a friend or playtester?
I'm pretty sure they have to be in the same folder. https://docs.textadventures.co.uk/quest/publishing.html
When you add a picture or a sound to a game, the file gets copied to the main folder in any case, so yeah, that's where they have to be.