mp3,
At one point in time, you couldn't walk either, or speak.

It's *really* not that hard to learn.
Take a look at
this link, and
this other link.
Contained therein you can find all the information you need to meet your needs and more.
The
Manual also has a nice section detailing WPS creation too, plus a lot of other stuff every Rockbox user should know.
Just remember that the people who know how to do what you would like to, at one point in time, did not know these things...
You can use the original images from the Cabbie3.0 theme for instance, but simply convert them to greyscale or B/W with a simple image manipulator such as
IrfanView.
After that, only a few simple changes need be made to the WPS code to achieve you desired effect.
I am happy to walk you through doing this yourself.
[St.]