You are asking the right question! While it is not possible to prevent
images from being downloaded (that is, after all, what browsers do), you
have certain means, just as the publishers of music and movies on DVD, of
seeking redress in court when your copyright is violated.
The use of a Digital Watermark is about your best bet. Check out
http://www.digimarc.com/.
--
HTH,
Kevin Spencer
Microsoft MVP
Professional Numbskull
Hard work is a medication for which
there is no placebo.