"Yes" to your first question and "No" to your second
question.
In order for an image to be viewed, the user's browser
downloads that image from your host. Users can then
manage to save that image whether or not the right click
is disabled.
This question gets covered quite frequently on the
various Front Page newsgroups so rather than me taking
the time to cover all of the various arguements and
possible work arounds, please take some time to look
through the newsgroups.