[Capability scenario] Pictures [Capability usage] 
The picturesLibrary capability provides programmatic access to the user's Pictures, allowing the app to enumerate and access all files in the library without user interaction. This capability is typically used in photo apps that make use of the entire Pictures library. The file picker provides a robust UI mechanism that lets users open files for use with an app. Declare the picturesLibrary capability only when the scenarios for your app require programmatic access and can't be realized them by using the file picker. For an example of how to access files in a library, see Quickstart: Accessing files programmatically.