© is easier than you may think.

I attended a Copyright Workshop on Saturday and learned some valuable information. The main thing that really shocked the entire group was that when an artist crates an original work of art she/he owns the copyright to it for a life time plus the next 70 years. It must have a “copyright notice”, © , placed somewhere but it can be on the back of the art and still be valid. It’s best to take a second step to register it with the Copyright Office.
www.copyright.gov See especially Circular#40 (Copyrights Registration for Works of the Visual Arts)
There were many other things I was totally unaware of that came up in the workshop. If you sell a piece of art the buyer cannot reproduce the work or use it without your permission.