This is only ONE of the many methods to protecting your art is to embed copyright. Take these steps to embed your copyright information in the EXIF data of your photos.
See how to embed copyright in Photoshop HERE
Some social media sites have gone as far as to read the copyright data inside and place it as your caption on the picture upon upload! Obviously this is not a full-proof way to safeguard but every bit helps. Some online uploads may strip the information but some will retain all embedded data such as your settings and this copyright information.
Is this going to stop people from screen shots or changing the data? No, but it can work as ONE of MANY safeguards to protecting your pictures.