Instagram now has 7m users who have shared 150m photos

Social service continues to grow rapidly, having added one million users in the last fortnight.

Social photo-sharing startup Instagram has announced that it now has more than seven million registered users, who between them have shared more than 150 million photos.

The service is currently seeing 15 new photos shared every second (which, doing the maths, means nearly 1.3 million a day). An impressive figure, given that the Instagram app is still only available on one platform: iPhone.

"We're constantly amazed by the range of photos shared on Instagram," blogs the company, pointing out that besides personal users, the service is also being used by artists, celebrities and brands.

Instagram's growth has been rapid. It launched in October 2010, and announced in mid-July 2011 that it had six million users and more than 100 million shared photos. That means it has added another million users in a little over two weeks.

The company is famously thrifty with its money too, with just four employees for most of its history.