So what if a user uploads a photo they don't own? If I take a group picture with my friends (but I'm not a Facebook user), send it (outside of Facebook control

So what if a user uploads a photo they don't own? If I take a group picture with my friends (but I'm not a Facebook user), send it (outside of Facebook controlled means) to one of those individuals pictured, and THEY choose to post it -- what happens, in this new scenario? The poster doesn't own the rights to the photo, and thus doesn't have the right to implicitly (via some EULA rewrite) grant Facebook the right to use it.