I've been working on a game and ran into the same issue as I did with previous games when creating the icon buttons. Which is that it takes quite a lot of time to export the button images from the original high-definition image if you do it by hand.
So I've created a GIMP Python plug-in that automates the processing and resizing of the final button images, while keeping the high definition original image unchanged.
I thought it might be usefull to anyone creating these kind of button images, so you can check it out at the GitHub link below https://github.com/BdR76/process_icon_buttons