[sdovan1]

I uploaded a photo and it took around 20 seconds. Maybe a loading indicator would help.

[gametorch]

Noted! Also adding predefined color palettes, like monochrome, sepia, etc.

I've found LLMs come up with really good color palettes, too.

[vintermann]

Yes, I didn't realize it would fit the palette too at first.

An interesting tool might be a mask tool, that let you highlight parts of the image to mark regions as weighted more highly in the clustering algorithm.

To be able to lock the palette would also be cool, but it would probably need some sort of dithering to be useful.