New Post: Known Background

Trying to do exactly this with Magick.NET

convert.exe overlay_figure.gif overlay_mask.png -alpha off -compose CopyOpacity -composite overlay_removed.png

http://www.imagemagick.org/Usage/masking/#known_bgnd

I have tried using MagickImageCollection, adding both images, but don't see options for -alpha and -compose, the best I could find was:

                result.HasAlpha = false;    
                result.Compose = CompositeOperator.CopyAlpha;

TIA