They shouldn't have. I've been using that link for my other gallery since I posted the original. I'll do more research and find the original picture along with the artist. Could be that they just changed their name? Thanks for bringing this to my attention! I really appreciate it.
Edit: this is the original picture. The artist is （憩）, but it seems all the links to their pixiv page have been changed or removed. :( I'll keep looking though!
That pixiv link doesn't seem to lead anywhere, did the user clear their gallery?
It's fine to just point to the original image, you don't have to find the artist. :) Thanks!