colorquant Color Quantization
Limits the amount of colors in a picture using color quantization, which is a process that reduces the amount of distinct colors in an image while maintaining a visually-similar image. The effect is similar to that of posterization, where decreasing the value of the
colorquant parameter will reduce the gradation of tone and create abrupt changes from one tone to another.
GIF files function on a limited 256-color palette, so animated GIF files will experience a reduction in size when limiting their color palettes.
Valid values range between