Pretty sure this is an third-party upscale.

This image is an MD5 match for the image at https://anime-pictures.net/pictures/view_post/425126

The purported pixiv source: https://www.pixiv.net/en/artworks/48456097
https://i.pximg.net/img-original/img/2015/01/30/20/40/26/48456097_p0.png
is lower resolution and has not been changed since 2015-01-30T20:40:26-09:00
(pixiv image urls look like i.pximg.net/img-original/img/YYYY/MM/DD/HH24/MI/SS/<IMAGE_ID>_p0.jpg
ie are filed by upload datetime in JST.
revisions change that url. (For an example, see the post history of this and its revision))