Generation of artificial images for analysis of filters

I offer two scripts which generate the following artificial images:
* Images of constant color
* Chessboard images of several sizes
* Slow motion variation images.
* Fast motion variation images.
* Colorcharts with for fixed values of saturation and value.
This set of images can be useful when an engineer needs to develop inverse egineer of filter, for instance. You know a priori the features of the input images, and thus, you can infer the behaviour of the filter.
The code is properly commented in English.

Any comment or suggestion is welcome.

Thanks.

Jesús Monge.