In GTA Vice City, if you want to change your player model, you have to download a player model and make sure that it contains player.dff and player.txd. Extract the two files and open your img tool. Search for the dff file and click replace. When you click replace, it will say that the file cannot be replaced, if that happens then you have to delete the dff and txd files and add the new ones. Then go to models, generic and delete the PLAYER.bmp file. If the bmp file is not deleted, when you start the game, you will have the new model but a f*cked up texture.