When you upload any image to anywhere, copyrighted or not, it becomes a target for anyone to do anything they want and say anything they want - legal, ethical, beneficial, hurtful, or otherwise. You can challenge them, sue them, or ignore them, but you can't stop them from doing things to your image.

With that in mind, I rarely post my images except the few I have here on APUG.

As to your particular issue, all you can do is to express your displeasure to your friend.