I have been doing a lot of research on .vms and .vmi files and I am currently developing a Python package to release to you guys that will hopefully help everyone do basic things like generate .vmi files and render / encode icon data.
To test the progress I have been making I ran a quick dump of all the Dreamcast save files and mini-games I could find, and I think the results speak for themselves.
If you'd like you can take a look here.
https://github.com/slurmking/vmu-Icon-Backups

There are over 400 high resolution gifs and icons for your archiving pleasure.
My end goal is to make sure that we preserve all the knowledge that we can, just learning how to read these files was a nightmare of scrolling through dead links and waybackmachine archives. If anyone has any questions about the .vms, .vmi, or ICONDATA file types / structure just let me know.