There a several scripts around that will disable the right click; however, there are just as many to re-enable it. Do a quick Google search for "disable right-click on website" and you'll see.
If you want to protect your images you might want to watermark them with a logo/copyright. At least by using the watermarks the images require work before re-posting or using if someone is trying to pirate them. I use a free tool Irfanview to batch process and add watermarks.
Its extremely difficult from preventing replication and pirating of images once they are on the internet. That's just the nature of today's playing field. The same goes with almost all web content. You need to add your copyright and if applicable trademark registrations as a start. As far as images, be sure to include all of your meta content as well as the watermark for the best designation of ownership.