No probs lol. I think saving/exporting would be a must have, but I also have two more suggestions that would make the program a powerful tool:
a - The ability to export a png of just a selected area (this would require adding a selection tool obviously).
b - Layers with opacity sliders. This may be harder to implement (or not, I really don't know) but it would allow users to rotoscope super easily. Then they could export each layer to a png and use something like Krita/Aseprite to touch up/add colour and pack to a sprite sheet.