Even though it can feel like second-nature to grant an app permission, look closely to make sure that what the app is asking for aligns with the service it's providing. Otherwise, you're freely allowing developers to peek inside your photos, know your location, and read your texts. In a statement provided to TechCrunch Meitu says that it does not sell data and that its "sole purpose for collecting the data is to optimize app performance, its effects and features and to better understand our consumer engagement with in-app advertisements." The statement goes on to say that Meitu encrypts user data to secure users against hackers. But in situations where you're providing access to your phone, you're right to be cautious. If you want to see how much access you've granted to the apps already on your phone — and, in some cases, adjust it — go to your phone's Settings. Clicking on each app will show you what it can access. Playing with filters is fun, as long as using them doesn't put you — or your data — at risk.