One of my favorite sites that help with my blogging needs is Dynamic Drive. It has a lot of free scripts for enhancing navigation and adding forms or effects on your sites. I have always referenced Dynamic Drive whenever I need to disable right-click on my blogsites. If you don’t fancy using watermarks, you can always use this script. That should discourage image downloads not permitted.
Here’s the link of the script that I use here and my personal blog:
More blogging goodies, here.