SupaDupa does not prevent people from right clicking on your photos, as there is no reliable way to do that on every browser. The fact is, if you put an image on the internet, there are ways to copy it, and nothing that can truly prevent it.
The very honest truth about saving photos from the web is that whether or not you can disable the right click (which is actually disabled on *some* of our themes already) there is nothing preventing anyone from screen grabbing the image either. It's a risk that you should simply be willing to take.
If you are concerned about copyright issues, the best advice is to ensure that under your terms and conditions you mention your copyright notice and any limitations you wish to impose so that your site usage is conditional upon those.
Additionally, you could limit the original photos you upload to no more than 1024px wide. This will at least dissuade anyone from printing the photos out as the quality will be severely affected and will counteract the benefit.
At this time we do not perform any automatic watermarking of your uploaded product photos, although we may consider this in future. For now, if it is important for you to watermark any images displayed on your website, then you can apply your own watermark in a photo editor before uploading the image.