PRIVACY: Read this before using FaceApp — you give up more personal data than you realize on this Russian-made app.

FaceApp, a smartphone app that allows users to apply filters onto selfies they upload, has grown in popularity again thanks to a feature that allows users to make themselves look older.

But cybersecurity experts have raised several red flags about FaceApp. It’s made by a Wireless Lab, a small company based in Russia and, according to its terms and conditions, your photos could be used in unexpected ways.

FaceApp’s privacy policy notes its affiliates and service providers “may transfer information that we collect about you, including personal information across borders and from your country or jurisdiction to other countries or jurisdictions around the world.”

FaceApp essentially owns images uploaded to its service and can use them in any way it wants. That could include anything from splashing your photo across a billboard to using it in the development of facial recognition technology.

Machine learning requires tons of data, which users have been happily uploading in droves in exchange for “free” apps and services.