Excellent tutorial! Thanks for posting. So does GIMP have a drag and drop function? I was thinking of experimenting and using the tank graphics from the old Steel Panthers Game and see how they'd look in DH.
No. You could try opening up the Steel Panthers file in GIMP, resize as necessary.. Then make up the 3 files in total, and then drop them into the necessary folders.
Or even, just make up the 3 files, don't resize and try in-game to see how it looks (as it is).
But you don't have to use GIMP, if you have photoshop, that may be better? With GIMP I can increase my viewing image to 800%, which is grand.
Edit: for trying stuff out, I'd only make up one image file.
Edit2: If you want to try something out very quickly: Just grab an image, 24-bit bitmap-it, name it T-L_PANZER C-GER A-STAND L-1.bmp... and paste it into the gfx/units/bmp folder... ensuring that you've made a copy of the original file first.. so you can put it back after... and fire up the game. You should see your image there, as all the files are there already in vanilla.