I have zero coding knowledge. How do I generate a set of images with randomized pixels?

I would like to generate a set of images, based on a preset shape template, but with different color fills in each of the shapes, randomly, and all images unique (1 or more shapes can have the same colors but not all of them the same in 2 images).

I want to generate about 10,000 of them, will it be a very heavy task?

Here's an example to give a clearer picture.