With all your hard work the last thing you want is someone coming along and stealing your work saying that it was thier own. Although your using Photoshop you can still get around copyright information (something I do not condone) but why make it easy for them.
This video will explain the basics of how and where you would go to put Copyright and image watermarks on to your pictures.
As a follow up to this video there is a "Batching" video which will explain how you would perform this on multiple images at the same time
