@mudcruzr thanks so much for these menus, they're really great. I was playing around with customising them for my CR10S, and ended up making a couple of Python scripts for creating and viewing the required images.
RRF-Gen.py takes pretty much any standard image and converts it into the mono image needed by RRF. So you can create your images however you want, then chuck them through this.
RRF-View.py provides a very bare-bones, terminal-based preview of the image you have generated.
This is a bit of an old thread now but I thought this was a good place to mention it! I hope someone finds these useful - I certainly did. By removing some friction in the image-creation process, I found it much easier to iterate and refine my tiny little images (for my fork of the @mudcruzr menus!).
Finally, I haven't really shared a project like this before, so, if anyone has any problems please let me know and I'll do my best?