Is there a way to prevent people from right clicking on an image that I am selling, so they can't take it for free? Renderocity made it possible to sell photos and renders, and I want to make sure I am getting my moneys worth posting them.

Disabling right click won't stop anyone who is determined to take the image. There are plenty of ways to get at it without having to do that. Best bet is to deface the pic with a watermark or repeated logo, as used by Alamy and other image banks.

Has anyone actually sold an image on Rendo? Just curious....

I haven't sold anything, not that I have anything worth buying.

To the OP, when you make an image available for sale, Renderosity restricts the size of the image displayed, and the max size that can be downloaded. I didn't realize that until a few weeks ago someone mentioned the couldn't see an image at full resolution. I have since stopped putting my images up for sale, since I haven't sold a thing, and I really post to share my work with those that might be interested. If they can't see the image at full resolution, it defeats my real purpose of posting the image.

Same here.... I tried it for a while (sometimes questioning the logic of trying to sell art on a website full of artists... ?), and never sold a thing.

I'd much rather put up the larger images (especially the TNA stuff) for people to enjoy. The comments and feedback I get are far more satisfying, and just knowing my efforts are being enjoyed is worth far more than a few bucks to me.