Copyright begins at the moment an image is created.
Photographers own the copyright to their images from that point,
with one exception: if they've signed a contract signing
ownership of the copyright over to someone else,
such as their client. Furthermore specific rights may be licensed
to parties in exchange for compensation.
Please following this link to the Library of Congress to learn more:
Straight to the basics: U.S. Copyright Office, Circular 1 \Copyright Basics\
Everything you ever wanted to know: Library of Congress Copyright Office
Lots of additional information here:
Patents, Trademarks & Copyrights
(link provided by Ben via KMcNeill.com, thanks!)
