Everyone's suddenly posting pictures of what they might look like when they're old. People are posting results on Twitter, and it's provided a few good laughs in our work chat. If you're wondering how they're doing this, it's by using an an app called FaceApp, which is now the top trending free app in the iTunes App Store. You can download and use for free for three days.

The app's privacy policy said it collects the pictures you upload to its service, so keep in mind that it's keeping the selfies you take. Also be warned that one developer, Joshua Nozzi, said in a deleted tweet that it appears the app may try to upload other pictures from your library. If you're concerned about this, don't give it access to your photos when it asks, just access to the camera.

There have also been concerns that the app was made by a Russian developer, sparking fears that the data shared with the app could be sent to the government there. However, the app's developer said this week that the app deletes the data after a couple days.

Here's how to try the filter if you want to get in on the fun: