Agreed, Photoshop is the right tool for the job here, not a command-line tool. Some images will need more colors than others, some will need more dithering than

Agreed, Photoshop is the right tool for the job here, not a command-line tool. Some images will need more colors than others, some will need more dithering than others; and the tool used here doesn't look like it picks palettes very well.