Pixel editor?

I’m fairly new to this and am playing with Microbits. I would very much like to know how to replicate the Arcade Sprite Editor in an extremely simple form - a monchrome pixel editor with no frills at all. I want a facility in MakeCode to bring up a pixel editor of a custom size, but I don’t know how to do this.

Is it possible to show me how to extract the editor and its various functions/shims/field-editor annotations etc from the rest of the Arcade package - which is pretty massive - such that I could pare it down to a basic editor? Currently the standard 5x5 pixel editor for Microbit images isn’t helpful as it can’t be customized and I don’t know how even to access its source code such that I could recreate my own version of it.