My ground_type_map0 makes the game crash

Hello everyone,
in the past days I've casually tried my had at mapping, after reading what tutorials I could find online I was able to create all the files needed for a multiplayer battle map.
However I've encountered problems when trying to load the map in game. All the files work with the exception of my ground_type_map0.tga.

I've used GIMP 2.10 to create all the files. I've read around that others have had problems with the ground_type_map with GIMP, I've read that paint.net should work, but I cannot save .tga files in 8-bit with it. As instructed my ground_type_map has 8bit precision, is 512x512 and for now only has black road parts and green grassland parts.

What should I do to create a working ground_type_map file? What exactly is the problem with GIMP and that file?(My grassmap.tga made with GIMP works just fine)

Also, the pack file with my new map is not able to load as Mod with the user.script trigger, right now I have to set it to Movie to make it work. This doesn't sit well with me, any ideas on why it's not working as Mod?

I am aware that it has been a long time since anyone posted in this subforum, I am nonetheless hopeful... and will be grateful to anybody who answers.

Never mind, I found out the problem. My image was RGB, it had to be "Indexed" in order to work. I managed make it work via GIMP with the default options for indexation with 256 colours.
Unforunately I cannot change the title of the thread...

Screw my second message, I had confused two identical files. GIMP's indexation is not compatible in any way with the game. The only way I've managed to produce a working ground map is with photoshop.
Sorry for the mess.