Thanks for posting about this topic. :)

Luminate is a startup that has received funding from various groups, including Google Ventures. The company adds social media widgets plus AdSense ads to images. It is currently in use at large media and magazine sites like those of CBS and Hearst Digital Media.

I do know if this is a revenue share, could be. If successful it wouldn't be surprising if it becomes a Google owned product.

I found a recent report in USA Today about it [usatoday.com].

...Luminate ...is positioned as a moneymaker for websites, allowing publishers to collect revenue by inserting Google ads on their sites.

For Luminate to make money, it needs to sign up lots of partners and have those ad links showing up in millions of photos.

Bill Maris, managing partner for Google Ventures, says "tagging" photos — identifying friends in pictures — is what built Facebook into the powerhouse it is today. He believes Luminate and its annotation, social-media and ad tabs can take online photo viewing to the next level.

Google Ventures invested in Luminate, because "when we see someone trying to improve the life of a user, and there's an opportunity, we're there."