Returns the bit depth of a GdPicture image.

public int GetBitDepth(
    int ImageID
);

Public Function GetBitDepth(
    ByVal ImageID As Integer
) As Integer

Can be: 

1. For 1 bit per pixel image.
4. For 4 bits per pixel image.
8. For 8 bits per pixel image.
16. For 16 bits per pixel image.
24. For 24 bits per pixel image.
32. For 32 bits per pixel image.
48. For 48 bits per pixel image.
64. For 64 bits per pixel image.