@cyberware Don't upload from third-parties please. I used the same exact information as you to find the original post. On the Zerochan artist page linked from this post there I was able to find our own artist entry for them. From there I opened each of their profiles and found that their tumblr had the post. So I updated the entry to include that tumblr and uploaded the piece form there.
Zerochan may have incomplete or incorrect information since they have no content rules. We have content rules however and are expected to maintain them. Part of maintaining source integrity here means making your best effort to find the actual origin of pictures and to update the artist entry for future uploaders.
Also note that artist request explicitly says you should not use it when the artist name is known. If you spent just a few minutes more looking at their profiles you would have been able to find their entry quite easily.