Every image already has a copyright.
I stand corrected.
Here are some common misperceptions and a very good article on the matter.

Permission is granted to freely print, unmodified, up to 100 copies of the most up to date version of this document from
http://www.templetons.com/brad/copymyths.html , or to copy it in off-the-net electronic form.
On the net/WWW, however, you must link here rather than put up your own page. [bold text by Admin....relevant to posting of article here] If you had not seen a notice like this on the document, you would have to assume you did not have permission to copy it. This document is still protected by you-know-what even though it has no copyright notice. Please don't send mail asking me if you can link here -- you can do so, without asking or telling me. The only people I prefer not link here are those who mail me asking for permission to link.
This article was originally composed in 1994. The latest revision was in October 2004.
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Edited by Admin ...as reposting in its entirety is itself a copyright issue.
Definitely worth a read, however....