Check source: this was posted from an IP instead of a registered account. There's a few other people posting with the same name but different addresses as well. I have little reason to think it's a third-party source but there's always the possibility.

WRS said in comment #2602252:

Check source: this was posted from an IP instead of a registered account. There's a few other people posting with the same name but different addresses as well. I have little reason to think it's a third-party source but there's always the possibility.

I checked the source, and there is nothing wrong with it.

“창작” is one of the post categories, similar to a flair on Reddit. In Korean, “창작” means “creation” or “original work.” This means that, unless the author of the post is lying, the image included in the post was drawn by the author themselves.

Also, if there are Twitter/X or Pixiv links containing the same images as those in the DCInside post, then the owner of that Twitter/X or Pixiv account is likely the same person who uploaded the post on DCInside.

Yeah, that's the exact category I checked to get the image. Compared to most platforms the repost volume isn't rampant (at least, say, not like on Arca, but most of the time those are the posts marked as translations or using the image for a fan fiction instead), but even then it's still worth doing due dilligence to make sure it's really the same person. As you said, "unless the author of the post is lying".