New Garmin GPS for tinkering!
we need the car to become a dancing girl.
Tried the old files, those had 18 frames.
Lets see what these are...

$file generic_arrow_.srf truck_blue.srf
generic_arrow_.srf: Garmin Bitmap file, version 2.00, 3024x84
truck_blue.srf: Garmin Bitmap file, version 2.40, 2881x80

ok, pressuming the height as 80 - 84, and that the frames are squares,
this would be 36 frames, for either, with a 1 pixel buffer.

The srf files... they are more or less standard bitmap files.
Looks like theres nothing good in the repos for opening or editing srf files yet.
Thats fine. Last time I hacked a garmin was a decade ago.
I think back then, I made the bitmap, and modified the header to match garmins nonsense.
Today, lets try to make a useable program to do this conversion, and put that up on github later.
https://github.com/FOSSBOSS/garmin