Product used : [MYKKUKKU] coloring JPG/PNG + color pallet SET_picnic
01. [Import] → Select coloring book png file
02. [Layers] → add Layer
03. drag added layer and move down the coloring image layer
04. How to use color swatches image : [Actions] → [Canvas] → [Reference]
[References] window is active, you can import colorswatch images from files and gallery apps. Long-click the color you want to use on the reference screen to extract the color.