An Alabama prosecutor's warning to parents about an app that can secretly store photos has gone viral.

Blount County District Attorney Pamela Casey took to Facebook to tell parents about an app that allows kids to store hidden photos in their phone.

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In the five days since Casey shared the video, it's racked up close to 3 million views and more than 1,500 comments.

Casey's video focuses on an app called Private Photo (Calculator%), which looks like a calculator, but is actually a hidden vault for private photos. It's just one of many apps that allow teens to store photos that they don't want snooping parents to find.

"Take a minute, grab that phone and look for the Calculator% app and make sure you stay on top of that with your children," she said.

Though these types of apps have been around for several years, judging by many of the comments on Casey's Facebook page, many parents were not aware of the app's existence.

"Thanks!!!! We need an app for parents to help us get the latest info to watch out for!" wrote one Facebook commenter.