Facebook is debuting facial recognition that will automatically notify users when their photo is posted; the feature is part of the social media company’s answer to criticisms from European regulators, the U.S. and elsewhere that it is disseminating fake news and hate speech, as well as not respecting privacy rights. The feature is based on technology already in use to suggest tags for people in posted photos. Although the company hopes it could help combat some abuses, it may raise more privacy issues.

Bloomberg reports that Facebook deputy chief privacy officer Rob Sherman says, “the new feature gives users more control by informing them when their photo has been posted.” The user can then review the post and tag or leave himself untagged, contact the poster to ask him to remove the photo or file a complaint with Facebook.

The notification will only be sent to users who are part of the permitted audience for the page posting the photo. Another feature will “also inform users if anyone across the entire social network tries to post a profile picture containing them,” said Facebook director of applied machine learning Joaquin Candela, who added that, “we’re doing this to prevent people from impersonating others on Facebook.” Both features can be turned on or off with a single toggle.

The new features will be available everywhere “except Europe and Canada, where privacy regulators have previously raised objections to Facebook’s auto photo tagging feature.”

Facebook product manager in the applied machine learning group Nipun Mather notes that the technology will not recognize faces that are obscured, in shadow or at unusual angles, and would “struggle to differentiate identical twins.” In those cases, Facebook will leave the person untagged. Facial recognition will also be added to its “automatic alt-text tool,” which provides an audio description for the visually impaired.

Wired reports that Facebook’s facial-recognition technology is “among the best in the world,” as “ the hundreds of billions of photos stored on the company’s servers provide ample data to train machine-learning algorithms to distinguish different faces.” Facebook’s AI research group did work on “a system that could recognize people even when their faces are not visible, using other cues such as clothing or body shape,” but that technology is not in the new features.

For users that opt-out of facial recognition, Facebook “says it will delete the face template used to find you in photos.”

Privacy advocates would prefer if the system required users to opt-in, rather than opt-out; Electronic Frontier Foundation senior staff attorney Jennifer Lynch “argues that Facebook’s current policy prevents people from being able to make decisions about privacy and risks to their personal data,” since “the company can instantly and silently roll out sweeping new uses for face data that affect over a billion people.”

Potential uses of facial recognition include retail, including in-store payments. Facebook “already works with data brokers to link Facebook users’ online activity and profiles with offline behavior,” but a company spokesperson said Facebook “has no plans for facial-recognition products beyond the one announced.”