COLOR THIEF
https://lokeshdhakar.com/projects/color-thief/
by Lokesh Dhakar
Grab the color palette from an image using just Javascript.
Works in the browser and in Node.
You can use the extracted palette to make your Tiddlywiki palette using kookma Colorplay
Note: For color palettes see also [tw5] Selectors (and Colorplay) - definitions and examples? - #3 by Mohammad