Like the ConvertTo1Bpp() function but without applying pixel color reduction. 

Use this function to convert a black and white image to 1 bit per pixel color palette. 

The color table has 2 entries: 1 Black & 1 White.

public GdPictureStatus ConvertTo1BppFast(
    int ImageID
);

Public Function ConvertTo1BppFast(
    ByVal ImageID As Integer
) As GdPictureStatus

A member of the GdPictureStatus enumeration.