Prevent saving images on vbulletin site?

[Fusion2]

Is there a way to prevent people from downloading images or forum icons on our vbulletin sites?

I don't mean disable right clicking etc. But, rather prevent them from doing a "save as" for images; or if they do save the image, it swaps it for something else, like a lower resolution image?

[Lynne]

If it shows up in the browser, it's in the browser cache and savable.