[userbinator]

mostly-uniform areas of color that have slight variations

That's precisely what it's attempting to smooth over - and it works well for anime images because in them, those variations would be considered noise.

Wondering if it would anime-ise it, I fed Waifu2x the standard Lenna image - twice - ended up with this:

http://i.imgur.com/iNWRjIS.png

[Malcx]

How did you achieve that? I've run it through several times and whatever settings I use, can't get anything close to yours?

[userbinator]

I took the original, scaled it down to 1/4, and then back up to original with Waifu2x at 2x scale, maximum noise reduction.

[zellyn]

That's fantastic!