This is where the INI file goes, you can have as mansy files as you need to so mess with the ones that come with the game.
C:\Program Files\EA Games\Command & Conquer Generals Zero Hour\Data\INI\MappedImages\TextureSize_512
This is where the actual images go.
C:\Program Files\EA Games\Command & Conquer Generals Zero Hour\Data\English\Art\Textures
Download a program called cameo mapper that will let you use a GUI to map the coordinates and it will write the ini file for you.
Mod Tools
They have it at thier site but that may be down soon for overhaul I have it mirrored at my site. It's not the most recent version but works quite fine.