This is an absolutely wonderful way to practice coloring. The process allows you to focus exclusively on textures and colors without having to worry about the over all structure of the design.

There might be problems with the copyright of the paint by number set. I suspect that most paint by number sets give people the right to share the colored image.

If that has you worried; you could generate a basic drawing with an AI image and then color the ai drawing. I've seen several people on Night Cafe do just this. They generate coloring sheets for their kids; so that there would be no questions of copyright.

!WINE