First things first, I do want to thank anyone who is considering on contributing here with map tile generation for both American Truck Simulator and Euro Truck Simulator 2!
Onto the main part of how to contribute here.
In order to generate tiles, you will need to latest pre-release from the TsMap repository. Do not worry about the source code.
Once you have the zip file, extract it anywhere you wish, then run the TsMap2 EXE file. From here, you will have the option of choosing the game, its main game directory, and mods. If you are contributing only the base game map tiles, do not select any mods and then select the JagFx profile when you select to Generate Map Tiles. By this point, you should be able to generate the tiles.
For Promods, during mod selection, only select the Promods map files as required.
If you are contributing other map mods, please be sure to note which maps you will be contributing to and what will be required, and for which game.
Note: You must own all DLC for the game of which you wish to generate tiles for.
Check your Output folder for the map files, and zip/rar them for easy uploading. I would prefer you have a name scheme like ats_v1.41.zip or similar. If it's a mod map such as Promods, please use something like ats_pro_v1.41.zip so I know which is which.
Now that you have a zip, it's time to actually contribute them! It's pretty simple, just open a New Issue and link the file using whatever service you prefer. Below, you can see a list of services you can use to send me the files. These are not the only ones available, and you are free to use whichever is easiest.
I want to make a mention that I do not personally use the Promods Map Mod for either game. Thus, I can't really generate the tiles for this purpose and this is where I will need help with. How fast they update, I'm not sure. If anyone is willing to generate those, by all means let me know!
While officially, the main repository will not hold additional map combinations, it may still be possible with different branches.