Description of the new feature/enhancement

Shadertoy.com has many amazing examples what one can do with what is called fragment/pixel shader. I would like to be able to download or implement my own pixel shaders and have that as a background in the terminal.

For exampel this one would be cool (making a bit darker to actually see the text) : https://www.shadertoy.com/view/3lyXDm

Configuring the feature be used using already existing background image but with support for shader file extensions?

"backgroundImage": "c:/myshader.ps"

"backgroundImage": "c:/myshader.glsl"