Stoopid Question: How2makecustomskins
Easy :D
Get GCFscape and VTFedit, make a folder called "TEXTURES"
Use GCFscape to open a source file for the game the texture comes from, they are in the folder
yourdrivehere:\Program Files\Steam\steamapps
The files are hidden, so you won't see them when opening the folder with Windows Explorer.
Now, navigate to your texture (.vtf file) and extract it to TEXTURES.
Note: REMEMBER THE FILE PATH, OR WRITE IT DOWN. SUPAR IMPORTANT.
You can now close GCFscape.
Open VTFedit.
Navigate to your texture, and open it. Export it to TEXTURES as a .png (or any other extension, .jpg is a bad choice though).
Open the .png in your favourite drawing program and edit as much as you like.
When it's done, open VTFedit again and open the edited .png file.
Export it as a .vtf to TEXTURES.
Now, did you write that file path down? If you didn't, go back to GCFscape and find your file
and write the filepath down.
You can now close VTFedit.
Open your GMod folder and go to the folder garrysmod.
(yourdrivehere:\Program Files\Steam\steamapps\yourusername\garrysmod\garrysmod)
From here, type in the file path. If a folder doesn't exist, make the folder.
It looks like this if you edited the Combine Soldier:
yourdrivehere:\Program Files\Steam\steamapps\yourusername\garrysmod\garrysmod\materials\Combine_soldier
Put the edited .vtf file in the same folder as you saw the original in GCFscape, in this case "Combine_soldier".
Note: GIVE IT THE SAME NAME AS THE ORIGINAL FILE
You're done!
Garry's Mod automatically uses textures that are in it's own folders instead of textures of the same name in source files.
