July 26, 2012
Background image of the back of the Tile. If this property is an empty URI, the background image of the back of the Tile will not change during an update.
Assembly: Microsoft.Phone (in Microsoft.Phone.dll)
XMLNS for XAML: Not mapped to an xmlns.
Secondary Tiles can be created only using local resources for images. For more information, see Tiles Overview for Windows Phone.
If the URI references an image that was stored in isolated storage, then the image must be in the Shared\ShellContent folder. For more information, see Isolated Storage Overview for Windows Phone.