Google and Facebook Inc are locked in a battle for social network followers that has increasingly shifted to mobile applications, such as photo editing.

While not as famous as Instagram, available for free on Apple's mobile devices, Snapseed has won a following for its editing prowess among photographers, despite a $4.99 price tag.

Nik Software says Snapseed has more than 9 million users while Instagram says it has more than 100 million.

"We want to help our users create photos they absolutely love, and in our experience Nik does this better than anyone," Vic Gundotra, Google's senior vice president, engineering, said on a Google+ post.

Facebook this year bought Instagram, which made an app for users to add filters and effects to pictures taken on their smartphones, for a cool $1 billion.

"Google's playing chase up in social," BGC Partners analyst Colin Gillis said. "It's yet another tuck in they have done, trying to boost their Google+ offering."

Snapseed won Apple Inc's "iPad App Of The Year" award in 2011 for its multitouch photo editing interface.

"We've always aspired to share our passion for photography with everyone, and with Google's support we hope to be able to help many millions more people create awesome pictures," Nik Software said on its Website.

Google's Gundotra also said that Google+ had hit over 400 million users this week and had just crossed 100 million monthly active users.

(Reporting by Sayantani Ghosh and Sruthi Ramakrishnan in Bangalore)

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