Pixazza, which is a similar service to Google AdSense but for images, enables publishers to tag products within images used on their sites and link them to shopping sites like Amazon and Zappos. So far the software has been used across fashion, home furnishings and travel.

The latest round of funding will support a self-service version of the technology, with revenue from advertising shared with publishers.

Publishers already using the commerce-enabled photo network include USMagazine.com and OKMagazine.com.

The company raised $5.75m 18 months ago from investors including Google Ventures and former Facebook CFO Gideon Yu. This funding round has also been supported by Google Ventures.

Last month, electronic goods user forums AVForums and ITProPortal became the first publishers to use geo-targeting ad platform Skimwords, which converts keywords and product references in editorial copy into geo-targeted links to where the item can be purchased, while video specialist How To TV has tied up with Ooyala to offer publishers interactive video technology.