It would appear the version of this image currently on Pixiv also features the same face changes as this version from Tumblr, but with a higher resolution (1447x2046) and no compression (png). This one doesn't deserve deletion via the flagging process for the provided reason since it's an "official" updated version straight from the artist, but it also doesn't look like it's the best quality revision currently available.
"This has been enlarged from the original. The original source for the image is Pixiv and is already on Danbooru. - about 3 hours ago"
You've got to be kidding me, the pic is taken from artist's tumblr like this one post #1786793 or this one post #1781318
He always posts there the best quality work, not on pixiv.
You are correct. I flagged this post as I wasn't aware Kawakami Rokkaku had a Tumblr page. Thus I surmised from the source that it had been enlarged for Tumblrs 1280px width. My fault, my lack of information, I apologize.