The colors in that image seem super bright compared to the original. https://www.moma.org/collection/works/79971?locale=en
The output for that version of the painting looks similar. I just image searched for "kupka" and tried a few different results. Result for your image: http://imgur.com/fp9i8BP Do you think I should update the repo with this version?
I do, only because it's from the institution that actually owns the real painting. Museums try pretty hard to get colors right on the digital images that they put online. And since the project is about color, it seems like an important detail. Thanks for being open to my nitpicking. Very cool project.