Thanks for putting this together. It solves the problems I was having with images and it seems a good method of modding in the future. Can the loadimage changes be put into the main code in the future or is there some drawback?
One thing I noticed was that the MAD script was called from ready() in exploration.gd. This is too late if you want your customization available in the start generation from the main menu (although you can easily copy some of the relevant code across).