In reply to Geoff S:
> I use Smugmug to host my website and they have a 'rightclick prevention' option to stop the simple 'save image' option.
It's not very good then - just allowed me to right click and save any of the photos (using firefox). Does a better job with chrome, but even then you simply need to find where your browser caches the files (the image has to be downloaded locally before the browser can display them) - something, I would imagine, the average image pirate is more than adept at doing.
Taking a screendump won't (necessarily) give you an image of the same quality as the file as someone suggested above - this depends on the display quality, tool used to do the screendump, etc. Irrelevant though, as you can always get the file one way or another. Your UK mountain photo of the year downloaded to my device as DSCF1193_edited-3-X3.jpg (for example).