That feature does not currently exist, but that is a great idea. I have added it to the list (which is just the github issue tracker, and contains no other item

That feature does not currently exist, but that is a great idea. I have added it to the list (which is just the github issue tracker, and contains no other items). I like that it auto-analyzes the palette when the images loads without requiring any further user input, but maybe an option after it loads to "auto-detect X colors" as a little dropdown thingie.