Facebook makes it so easy to steal images completely or share them through FB that, sadly you just have to weigh the benefits versus the loss because there's not much you can do about it. Fortunately the image they can steal is not up to the quality of the original, but for someone just using it on a social media page, it's good enough. Recently, I noted an FAA "Recent Sale" and realized that I'd seen many times over the years, all over the place, with no attribution at all, and when I looked for the work of the person on FAA whose image had sold, his style (a painter) in other images completely matched the style of the image I'd seen elsewhere. I concluded that his picture had been lifted some years ago and took on a life of its own, like it or not, to no benefit to the artist. I would suspect that most of the people that use it have no idea where it came from and use it because it's just "out there".
