Images. Aseprite workaround isn't much better, because Spine just upscales pixels with no filtering/sampling (which pixel art hates, anyway), so jaggies get scaled, too.
Like so. It's pretty visible how 400% scale just quadrupled the problem, instead of filling in missing pixels like RotSprite would.
My method still seems to provide at least a little bit less quality loss. Not every single pixel line turns into a lighting bolt.
I think that giving pixel artists a break with this wonderful tool would increase popularity and usability of Spine a lot. Not all artists do vector art.
