It isn’t an exaggeration to say that Facebook houses the largest collection of images in human history, with an estimated number nearing 1 trillion. Of course, with that many pictures, Facebook has sought out ways to capitalize on it, including with its “Tag Suggestions” tool that scans every picture you upload and identifies your friends’ faces. But with that kind of huge database comes plenty of potential privacy issues, as a recent class action lawsuit pointed out.

According to the suit, “Facebook conceals that Tag Suggestions uses proprietary facial recognition software to extract from user-uploaded photographs the unique biometric identifiers (i.e., graphical representations of facial features, also knows as facial geometry) associated with people’s faces and identify who they are.” The case was filed by three individuals in the state of Illinois, where a 2008 law called the Biometric Information Privacy Act  (BIPA) requires companies to obtain direct consent from consumers before their data is collected.

While it may be tricky to fight this biometric data-hoarding in other states, the issue has a real chance of coming to a head in Illinois. According to privacy experts, the problem isn’t necessarily that Facebook is collecting data, but that the site is using that information to create profiles of users.

“If you run a bar, the law doesn’t prevent you from picking up my used pint glass, but it prevents you from pulling my DNA off it,” said Alvaro Bedoya from the Center on Privacy and Technology at Georgetown Law.

Of course, Facebook has filed to dismiss the case, but the outcome could potentially still have big ramifications for the future of every user’s picture privacy.

Unfortunately, you can’t opt-out of Facebook’s photo tagging feature, the best thin you can do is enable the tag review feature.