When using the Xamarin LinkOS sdk to store an Android.Graphics.Bitmap object for later printing, are there any requirements as to the format or type of Bitmap?  The reason I'm asking is that when I go to print the bitmap, all I get is a solid black rectangle where the bitmap should be.
 
The bitmap is generated by the Xamarin signature capture component, it is being stored on the device using the StoreImage call on a scaled copy of the bitmap, and is being printed by a ^XG statement.  The rest of the label prints without issue, and a static logo on the label also prints fine.  It is only the signature capture bitmap that is causing headaches - all I get there is black rectangle.
 
Any suggestions would be greatly appreciated.
-David