How to organize the painting of 1000+ cars for the site?

Question

Automation

Coolity to everyone.

I took a piece of the script and decided to tinker with it.
There is a game about cars (stupid text wap game)
There is a tuning in it that allows you to paint cars (here I am aul) but how to organize car painting?
By default, the types that wrote "tuning" simply painted the car in different colors in advance (filled it into a folder with cars) and when you click on painting, they simply give back the pre-painted car (which they painstakingly painted in PhotoShop)

Actually, the question is, how to simplify the process?
Here is an example, there is such a thing. It is
necessary to get such a thing . It’s

stupidly unrealistic to do this manually (maybe there can be 1000+ cars, 20 colors as a result of 20k pictures? no, bullshit)
from the toolkit I have python django I can do a bit of js (and of course html css)