So recently I've been facing a bit of a dilemma, especially in regards to my art from pixiv being uploaded to a deviantart account with a linkback, but it does pose the question- when it's clear that the art is not by you, why are you uploading it at all?

I ask this because art that I had not posted to dA was reposted here (without my permission, as well)- being fanart, I'd even be okay with some reuse as I'm not making money off it, and neither is the user, but even so. I didn't want it up on dA for a reason.
The artworks in question are here, uploaded without my permission by ~WangYiSanniang :

- :thumb272022505:
- :thumb272023130:
- :thumb272020848:

An attempt to let the poster know that this wasn't okay was met with a careless "It has a link back, so it's all right" [ screencap ]

So, how much of an original piece does a picture need to be before it's considered the creative property of someone else? :\ I'm usually lenient with use of my art as long as there's a linkback, but dA isn't that kind of forum, or did the rules change when I wasn't looking? Suffice it to say, I'm a little peeved right now. :'D

Edit; After everyone's advice, I went and added a note to the original picture link on pixiv, in both Japanese and English (it's google translated, eheh.) But I think it's good enough for the 'more information' that dA wants. Thank you for all your help. I just love the excuses the other person is making right now too :'D