Conceptually, could once create a div, display the content and then put a transparent div over the content so if the user right clicks -> Save As, Save Image, etc and they won\'
An empty div would still make the content below clickable. One technique sometimes used is to do a similar thing, but use a transparent gif or png which would cover the content, or to use javascript to disable the contextual menu.
In any case, if someone wants to save the content, there's not really anything you can do to stop them.