Feel free to get as off-track as you want, it's O.K. with me. 
There is no way that you can avoid anyone that wants your picture, as you're probably aware, most don't know that they are really hurting a thing, they see it as borrowing, it doesn't affect them until
someone does something similar to them, then they can get mad.
It's so easy to get rid of copyright information on most pictures, I know how easy it was when I did Photoshop for a living, (I didn't do it, I just knew how to delete anything) but from what I have read there are ways to really do it better now.
We've all seen the guy that shows his GIANT logo that is repeatedly placed across his image, that is the only true way to make them think twice about your image. I hate those, but it is about the only way I know.
That's really too bad about how they did that to you, it's really amazing how they can treat others, thankfully at least on Facebook you can shut them down. I will say that when I told them that 'young guy' that stole my image they took care of it, although it did take me awhile, I had to jump through hoops proving that it was my image.
Randy