Instagram has been hit by a civil lawsuit in the wake of its ill-advised attempt to change its terms of service last week, a move that was hammered by hundreds of critics and led many users to threaten to quit using the photo-sharing app altogether.

Responding to this outrage, Instagram quickly backpedalled and announced that it would be reviewing the changes made to its TOS, claiming at the time “it was listening” to its users’ concerns. It later announced that it would be reverting back to the old TOS for the time being.

The big issue of contention was a new clause inserted into the TOS, which seemed to give Instagram the right to sell user’s photos to advertisers without having to pay any kind of compensation, or even inform people that it was doing so. Naturally, most people didn’t take too kindly to this kind of stipulation, which users could only opt out of by deleting their Instagram account entirely.

While Instagram has reverted to its old TOS, it did choose to retain one clause from the new version which allows it to place adverts ‘in conjunction’ with user’s images:

“…we may not always identify paid services, sponsored content, or commercial communications as such,” it adds.

Unfortunately for Instagram, it appears that at least one user has taken exception to that particular clause, according to the technology news website Slate.com. Over Christmas, the San Diego-based law firm Finkelstein & Krinsk announced that it was filing a civil case against Instagram on behalf of its client, an Instagram user known as Lucy Funes, together with other persons “similarly situated”.

According to the lawsuit, Instagram is accused of breach of contract. It argues that the only get out clause a user has, should they disagree with the new TOS, is to deactivate their profile, a step that would cause them to forfeit their rights over previously uploaded photos. Even worse, Instagram would be absolved of any legal liabilities according to the new TOS:

“In short, Instagram declares that ‘possession is nine-tenths of the law and if you don’t like it, you can’t stop us.”

Facebook, the beast behind Instagram, has stated that it will fight the lawsuit, insisting that Instagram’s actions have been entirely lawful:

“We believe this complaint is without merit, and we intend to fight it vigorously,” announced a Facebook spokesperson.

According to the law firm Finkelstein & Krinsk, thousands of Californian Instagram users are eligible to add their names to class-action lawsuit. To date, the court is yet to decide whether or not it will allow the case to proceed.