News of the new feature was shared on Twitter by a user who posted an image of a screenshot warning message. Instagram plans to offer a one-time warning letting screenshotters know that subsequent screenshots or screen recordings will be visible to the person who posted the story.
The feature is being tested with a small number of users. Participants can see who took a screenshot of their story by going to the list of story viewers and checking to see if there are camera icons next to any of the names. A flash icon denotes a user who took a screenshot.
Instagram does not plan to send out notifications when a screenshot of a story is captured, but it will be visible in the list of people who viewed the story.
PSA: How you get notified on Instagram when someone took a screenshot of your Stories pic.twitter.com/Iua2QeyskF— iz reading On the Edge of Scandal 🍑 (@readbyher) February 11, 2018
Instagram confirmed to TechCrunch that the feature is in testing right now: "We are always testing ways to improve the experience on Instagram and make it easier to share any moment with the people who matter to you."
It's not yet clear if and when Instagram will officially introduce this feature.