Obviously not putting the images online would stop a person from
hijacking your images and watermarks will also slow it down as well.
One of the things I have noticed is that if you use Flash for your
images it will not let you access them too easily either although it is
not impossible to get them in most cases people are not interested
enough to go through the effort to get your images. I would take a look
at a few of the musiums websites like the one at the louve for ideas on
how to protect your images personally. While those images are not
protected they make it difficult to get at them individually especially
for a novice. It all boils down to the old attage if a person is
determined to steal from you they will. The only thing you can do after
they do is go after them with legal actions for damages. Disabling the
mouse button is not a good idea in general as there are many people who
use that for navigation and that can effect your accessibuility for
handicapped or impaired visitors.
)