FaceApp, the viral app that makes you look old or young, now has a new warning when you take a picture. It helps address some of the privacy concerns , particularly around the original lack of disclosure that it was uploading your pictures to its servers for processing.

Now, when you take a picture, it says: "Cloud Photo Processing: Each photo you select for editing will be uploaded to our servers for imaging processing and face transformation." Users can decide if they still want to proceed, or if they prefer not to give up their picture.

FaceApp told CNBC on Wednesday that it only uploads the photo selected for editing and that it does not upload any other images in your library. It said most images are deleted from its servers within 48 hours. It also said that while the company's R&D team is located in Russia, it doesn't transfer user data to Russia.