Google may not be buying companies as often as it once did, but that’s not stopping it from doling out funds to promising start-ups.

On Wednesday, Mountain View, California-based Pixazza, a developer of photo-based online ad technology, said Google was among the group of investors that plunked down $5.75 million in Series A funding. Pixazza’s technology lets Web surfers click on portions of online images to get more information, say the brand and price of the shoes that a celebrity is wearing in a photo.

“Google’s investment underscores the innovative and promising nature of Pixazza’s new advertising technology,” Pixazza said in a statement announcing the deal.

Google’s investment comes as the search giant has slowed its pace of outright acquisitions, and as the company prepares a new in-house venture capital division called Google Ventures.

Other investors in the funding round include August Capital and CMEA Capital. And Pixazza listed angel investor Ron Conway, former eBay COO Maynard Webb, and Facebook CFO Gideon Yu among its backers.

Pixzazza says its “distributed workforce of product experts” can match products in photos with its network of advertisers, and claims it will do for images what Google’s AdSense advertising network did for Web pages.

(Screengrab on March 26, 2009)