gbadevKasumi @ GBADev Discord server presented some work-in-progress footage of their homebrew animation program for Nintendo DS (with an enhanced PC port in the works):
"[..]Bitmap based, painting with opacity blending, line tool, fill tool, selection tools (copy/paste, paint masking), multistep undo/redo, compression (to allow more frames than like 24), many zoom levels, arbitrary canvas size (RAM dependent/certain sizes don't scale properly for playback, but it doesn't affect editing)"