Problem with reskinning

So, i’m trying to reskin a model. Here’s what I do, with GCFscape i grab a vtf file, with VTFEdit i change that vtf file into a TGA file, I open GIMP and change a few things, when I’ve finished, with VTFEdit I change the reskinned TGA file into a vtf file, then i put the file in the original directory and replace the old file with my new reskinned file. When I launch Garrysmod, the model is the same.

What am I doing wrong here!??!