The WriteableBitmap.
ToByteArray(WriteableBitmap) Method
Copies all the Pixels from the WriteableBitmap into a ARGB byte array.
Syntax
[Extension()]
public static byte[] ToByteArray( 
   WriteableBitmap bmp
)

Parameters

bmp
The WriteableBitmap.

Return Value

The color buffer as byte ARGB values.
Requirements

Target Platforms: Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

See Also