Windows Phone 7 – Integrate your App in standard picture viewer

With Windows Phone 7 you can integrate your own application seamlessly into the Windows Phone built-in photo viewer. The key to this feature is the Extras.xml file.

You have to place a new xml file with the name Extras.xml to your Windows Phone 7 project root. Set the properties to Copy to Output Directory and select Copy always.

   1: <Extras>

   2:   <PhotosExtrasApplication>

   3:     <Enabled>true</Enabled>

   4:     <StorageFolder>Incoming</StorageFolder>

   5:   </PhotosExtrasApplication>

   6: </Extras>

For the StorageFolder attribute you can choose your own name.

More informations you could find here: How to: Create a Photo Extras Application for Windows Phone