Earlier quoted context omitted.
This doesn’t at all address the primary issue, which is one of licensing. Is it a valid defense against copyright infringement to say “we don’t know where we got it, maybe someone else copied it from you first?” If someone violated the copyright of a song by sampling too much of it and released it in the public domain (or failed to claim it at all), and you take the entire sample from them, would that hold up in a le…
It does address it, although not that clearly. This happens all the time with news media. They will post a picture and say they got permission from X person, but X person actually didn't even own the copyright in the first place. That doesn't make any of it okay, but it does mean that the organization has legal cover in this case and the worst that will happen is that they'll have to take the content down. In GitHub'…
There is no “I don’t know who owns the IP” defense: the image has a copyright, a person owns that copyright, publishing the image without licensing or purchasing the copyright, is a violation. The fine is something like $100k per offense for a business.