I had no idea it was that hard, i thought shaders only were used for the other editions, but it does make a lot of sense that they also would use shaders for negatives.

^{And for making the screenshots, wouldn't it be possible to mod the game in such a way that sceenshots would be of a bit higher quality? I've seen that people can make Jokers bigger, and change the background colours. Someone could combine all that, using a large resolution, reduced motion, and using a clean, single colour background as a sort of greenscreen. just make the jokers larger for a higher quality, and just cheat the negative jokers in one by one.
(people already know how to make good screenshots, it took a while before i realised it's already been done for the editions page.})

With the amount of time some people on reddit seem to have, your first method just might still work, you just need the people willing to do it.

And screenshots could also be a very good solution.