Disable right click not working
Disable right click is only a deterrent, not preventive. It is impossible to prevent people from downloading your thumbs (or samples), matter of fact that is how the internet works. In order for someone to view your website they must first download the entire page (actual HTML coding, and all files like thumbs or samples to display). Then the browser takes that download data and constructs the page for the user to view it. That is just the way the internet works and it is impossible to fully prevent someone from downloading your thumbs (or samples).
Even if you could completely disable right clicking, it will not prevent people from dragging and dropping, or taken a screen shot for example.
The best preventive measure to stop people from stealing your thumbs (or samples) would be to watermark everything. Build a watermark that has your name or website name on it, so even if they did steal it, your name will be on it. Make your watermark big and cover the entire photo so it is almost impossible to photoshop out.
Ok so is there a way to completey prevent someone from stealing my thumbs?
No it is impossible to stop someone from taken your thumbs if they want to. The only true way to prevent it would be to not have a website, and not upload your images anywhere on the world wide web.