But...If you want to do it very quickly and not deal with the quite dense ImageMagick docs this is way easier.

When I want to do this and something else, two hours reading the ImageMagik documents will save me six hours of trying to remember this site and Googling around for a free service that does the other thing...and probably two hours of getting them to work together as a pixel pipeline.

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.

This is why I don't let myself become dependent on random internet services[1]. Apps on my machine only change or go away when I want them to.

[1] No offense to the site maker - the palette extractor is cool!

I think the site is great too. ImageMagiK's output is not quite as self explanatory nor visually appealing. Since I deal with hundreds of images at a time, though, I have learned to think in terms of a pixel pipeline.

I also try to avoid the overhead of managing emails and passwords.

convert path/to/img -colors 16 -unique-colors txt:-

That is really simple.