I'll help you out. First, download Warcraft III Image Extractor, I think it is on this site. Now, find the skin that you want to edit. Save it in TGA format. Now, open up the skin in the GIMP or any other image editing program. Begin skinning. Once you are finished, save it. Now, open the image you edited in the Image Extractor, and save it as BLP format. If you don't know how to import your own skin, open the import manager in the world editor, import the BLP skin, and change the path. If you edited the Evil Arthas skin, for example, it would be Units\Undead\EvilArthas\UndeadArthas.blp because those are the categories the texture falls under in the extractor. I hope this helped you, SuPa-. Happy skinning! If there's something in here you don't understand, let me know, hopefully I can help.