But...If you want to do it very quickly and not deal with the quite dense ImageMagick docs this is way easier.
Or at least that's what I have realized about reading documents over the past year and a half...Google lets me avoid reading documents it does not save me time.
[1] No offense to the site maker - the palette extractor is cool!
I also try to avoid the overhead of managing emails and passwords.
That is really simple.