Disable the “right click” ability.
Please be aware that this will only stop novice web surfers. There are so many ways to bypass any of the “no right click” scripts. If a visitor is on your site and wants to take the image or is there specifically to take your images this will have NO effect – taking the image is as easy as if the script weren’t there. This will however annoy visitors who legitimately use the context menu to navigate pages ( which is produced by right clicking )