User blog comment:Semanticdrifter/The CC-BY-SA License and You/@comment-954127-20120717222227/@comment-5473581-20120720064315

Side-stepping whether fair use collages are under CC-BY-SA, collages are still derivative images which the uploader has put work into, and if someone copies it, they're still re-using the uploader's work and should link back to the source. ("Should" being more of a courtesy rather than legal requirement)

I believe the fact you don't "own" the copyright of an image you have edited and uploaded, doesn't mean that your contribution to the image should be completely ignored. Is this wrong?

(I know the issue gets even trickier still when another user is obviously re-uploading images which are unedited fair use images which are widely available anyway, so let's just stick with talking about clearly edited images like collages which have been created by the uploader themselves. Although I believe all sources should be credited, even as a "finders credit")