Some of you guys have a lot to learn about copyrights law. "We" do it all the time on this site, but if someone ever came along and got snotty, it would HAVE to be removed.
Photos and other materials do NOT have to be officially copyrighted, or annotated as such on any website. One of you mentioned "public domain." Just because you have the electronic ability to copy and save material does not make it legal.
The point is this-----------if the OP does not want his photo used, he can demand it be removed, plain and simple.
It's easy to prove whether some photo came out of the same electronic camera, because all camera files "leave tracks." I'm not talking or limiting to the usual "EXIF" data, but more imbedded code in a photo, which can be tracked to a specific type and in some cases one specific camera.
(Of course if someone "photos a photo" this goes out the window, and you are left with camera angles and details)
So unless your evil twin was standing right beside you with HIS evil camera.......................