Shedding a little light on the state of the company’s social network, Google’s Vic Gundotra shared Monday that the social network now has 100 million monthly users.

Google folded the critical number for its Google+ network into a statement announcing its acquisition of Nik Software, which makes the photo-editing application Snapseed.

Gundotra, Google’s senior vice president of engineering, said that the site has 400 million registered users and 100 million active users, a year after the company launched its social effort.

Gundotra announced at Google’s I/O conference that the site had 150 million monthly active users, a discrepancy that VentureBeat explains comes from a numbers game. The higher number, the site explained, comes from those who click on a “+1” button or somehow interact with the social layer that blankets services such as Google search, YouTube or Gmail.

The 100 million active users, the report said, comes from those who visit the Google+ desktop site or use its mobile app.

No matter how you slice it, Google still has a long way to go if it wants to catch up with its main social competitor. At last count, Facebook had 955 million active monthly users.

The photo-editing deal could help Google+ become a more attractive platform for photographers, who could shoot better photos from their smartphones to upload to the network. Snapseed is one of the most powerful mobile photo-editing apps for the iPhone, though the company currently doesn’t have a version of its app for Google’s own Android platform. It may also be able to add more functionality to Google’s Picasa service, which has been closely integrated with its social networking service.

The acquisition could be seen to heighten the battle between Google and social juggernaut Facebook, which has been making improvements to its own photo-editing technology with the acquisition of Instagram. Unlike the Instagram acquisition, however, the Nik Software deal doesn’t add an existing group of socially networked photographers to Google’s fold.

Photos are a core component of social networking, however, and Facebook has reported that its users upload around 300 million photos a day to its site.

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