Attached Link: http://mysmithmicro.com/marcom/eblasts/photozoom/20130416/index-web.html

Has anybody tried this (or an earlier version) as a possible enhancement for 3D renders?

It's too pricy for me, even with 50% off, but if anyone else feels like being a guinea pig, have at it. :)

• Clarke's Third Law: "Any sufficiently advanced technology is indistinguishable from magic." - Arthur C. Clarke  

There's a free trial here.

It's hard to imagine that detail can be added to an image that isn't there in the first place, and I think the program just reduces jpg artifacts.

I've been using photozoom since version 2.  It's not perfect but in my opinion it does a pretty good job.  I've always purchased it from BenVista there are examples and an explanation on how it works.

Yeh, I have been using a photoshop plugin (a Fred Miranda plugin) for about 10 years that does the same thing. Basically it uses something called "stair" interpolation - they found that with different alogorisms and sharpening applied incrementally, you could retain detail better when enlarging a photo, then you could if you just used (lets say) bicubic once to get to the same size image.

Detail is added to new pixels, by averaging the data in surrounding pixels.

Photozoom works differently then that AFAIK. What it does is essentially take your image, converts it to a vector image (as best it can) then resizes it and then back to pixels. Since vector images can be resized to arbitrary sizes without loss of quality, as long as the initial conversion is good enough, you wont lose any detail in the resize, though you wont of course get any extra detail either.