Facebook is rolling out new features to help users report suspected "revenge porn," or intimate images of a person shared online without their consent, and block users from reposting the images.

The details: Users can report suspicious images, which are then vetted by Facebook staffers. The company says it will deploy "photo-matching technologies" to recognize if users are trying to share the image again — across Facebook and its Facebook Messenger and Instagram apps — and stop them from doing so.

Why it matters: The sharing of explicit images without the permission of their subjects has become a pernicious and persistent problem online, including on Facebook. It recently emerged that explicit images of female members of the military were shared in a Facebook group called "Marines United," which had thousands of members. The issue has attracted attention from Washington, as well.