is expanding the use of its facial recognition technology to alert users when a photo of them is posted, even if they're not tagged.

The idea is to round up photos posted by friends that you might want to add to your profile and to detect when someone else is using your photos as their own.

The setting is optional and tied into your current use of the site's facial recognition software, which suggests friends to tag in your photos — if you've got that feature turned on, then you would get these new alerts unless you opt out.

"You're in control of your image on Facebook and can make choices such as whether to tag yourself, leave yourself untagged, or reach out to the person who posted the photo if you have concerns about it," the company said in a statement.

The alerts notify users when a friend or someone in their broader network posts a photo "that might include you," and then offers options to ignore the photo, tag themselves, mark that it's not them or report the photo.