New idea for the image editor, specifically for animation of sprites:
A checkbox labeled "Propogate Changes." When you check this box, all actions you do on one frame will be repeated on all the other frames. For instance, placing the hotspot, flipping x or y, selecting an area of color, erasing the area of color, etc.
The selecting an area of color I think would be the most difficult part, because an animation will have that color in different places on each frame. But it would be useful for removing the transparency color from the background of sprites imported from a sprite sheet all in one shot.
Anyway, most tools wouldn't need to have any extra special attention paid to them. A pencil mark on one frame would make the same mark on every frame. It's just tools like the select-area-of-color tool that would need special attention. Crop is another, because some frames the area to trim transparent pixels might be larger than in others.
This would make the process of importing sprites a whole lot easier, since right now it's like an assembly line of flipx-nextframe-flipx-nextframe-etc, placehotspot-nextframe-placehotspot-nextframe-etc that just bores me to tears and is another reason on the list of why I hate making game art.