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Continue to ChatQuery : Command line interface-based way to desaturate and posterize an image? This is by far my most common task, and I'd say I've wasted about 1000 mouse clicks on it in my raster-based program. https://vmapp.org/query/512/Command-Line-Interface-Based-Way-To-Desaturate-And-Posterize-An-Image-This-Is-By-Far-My-Most-Common-Task-And-I-D-Say-I-Ve-Wasted-About-1000-Mouse-Clicks-On-It-In-My-Raster-Based-Program/