National Geographic, with more than 600,000 followers on Instagram, has followed the lead of hundreds of professional photographers in protesting Instagram's new terms of service.

Unveiled late last week, the new terms appear to allow Instagram to sell its users' images to third-party organisations for commercial purposes. The terms read: "You agree that a business or other entity may pay us to display your username, likeness, photos (along with any associated metadata) and/or actions you take, in connection with paid or sponsored content or promotions, without any compensation to you."

The modified terms have caused worldwide protests among Instagram users, with established photojournalists condemning the terms. Speaking to Time magazine, VII photographer Tomas Van Houtryve says: "Working as a professional, I would never use someone's likeness for advertising purposes without first obtaining a model release. By grabbing rights beyond social sharing or even editorial use, they've crossed the red line."

The high-profile protests – National Geographic, one of the first organisations to establish a partnership with Instagram, and one of the leading proponents of the service among photojournalists, has stopped posting new photos to its feed – have forced Instagram's co-founder Kevin Systrom to clarify his intentions. "We've heard loud and clear that many users are confused and upset about what the changes mean," he explains in a blog post. "I'm writing this today to let you know we're listening and to commit to you that we will be doing more to answer your questions, fix any mistakes, and eliminate the confusion. As we review your feedback and stories in the press, we're going to modify specific parts of the terms to make it more clear what will happen with your photos."

He adds: "Our intention in updating the terms was to communicate that we'd like to experiment with innovative advertising that feels appropriate on Instagram. Instead, it was interpreted by many that we were going to sell your photos to others without any compensation. This is not true and it is our mistake that this language is confusing. To be clear: it is not our intention to sell your photos. We are working on updated language in the terms to make sure this is clear."

Instagram is now expected to release updated terms of service in the coming days, but already some of its 100 million users have turned to other services such as Flickr, which last week unveiled a new version of its iOS application.

BJP will continue to monitor the situation and will address its consequences on professional photographers' work online in a follow-up article later this week. Stay tuned.