Instagram has added a new two-factor authentication security feature to the image-sharing application, more than two years after it was first announced.

Photo-sharing app Instagram has seen 100 million users sign up within nine months, taking it to 400 million worldwide.

Photo-sharing social network Instagram has come under fire for new terms of service which allow it to sell people’s own photos to advertisers, without paying them.

Facebook’s defensive purchase of Instagram raises a red flag.