The Coloring Game series will have a new addition this spring with a new game, Coloring Game: Studio. Now you can not only paint pixels by numbers, but also change the color and pixels of the base pictures.
The game will be premium (not free).
https://store.steampowered.com/app/2231040/Coloring_Game_Studio/
In the meantime, we are waiting for the release of Coloring Game: Studio, you can play Elle Demo.
https://store.steampowered.com/app/2291410/
https://store.steampowered.com/app/937930/Elle/