Pictures appear on the smartphone photo sharing application Instagram on April 10, 2012 in Paris, one day after Facebook announced a billion-dollar-deal to buy the startup behind Instagram. (THOMAS COEX/AFP/GETTY IMAGES)

Instagram has released new user statistics— perhaps in an attempt to head off speculation that the photo-sharing service is suffering following its terms of service controversy.

According to the company, however, nothing could be further from the truth. The service’s membership has grown 10 percent month-over-month between December and January, the company said. It now has 90 million monthly active users and says its users post 40 million photos every day.

Those of you with long memories may remember that Instagram was boasting 100 million users in September, but that was simply the number of people who had registered for the service. The 90 million figure is far more illustrative, as it gives a better idea of who’s sticking with the photo service on a regular basis.

There have been scattered reports that Instagram’s user base dramatically dropped since the company proposed — and then retreated from — changes to its terms of service related to advertising. The New York Post reported last month that the service’s active daily user count had fallen to 12.5 million from 14.5 million on Thanksgiving.

But as All Things Digital’s Mike Isaac reported, there are some factors apart from a user exodus that explain those numbers. For one thing, many third-party analysis firms don’t have access to all of Instagram’s member base, but rather just to those who have linked their Instagram accounts to their Facebook accounts. But Instagram was a full-fledged service before it was acquired by Facebook and many of its users said they did not want to link their accounts to the social network.

Isaac also noted that daily activity numbers tend to be more volatile than monthly figures. People may not have been using Instagram during December for any number of reasons — such as wanting to set their phone aside during the holidays.

(Washington Post Co. chairman and chief executive Don Graham is a member of Facebook’s board of directors.)

Related stories:

Instagram reminds users of privacy policy change

Instagram outrage reveals a powerful but unaware Web community

Facebook acquires Instagram for about $1B

Sign up today to receive #thecircuit, a daily roundup of the latest tech policy news from Washington and how it is shaping business, entertainment and science.