main thing is have the imaged indexed . Take a stock pcx into cs5 and look at eveything in the image size , resolution , and see what it says . Make yours exactly like that and you got it . I make all mine at 1024 x 1024 24 bit, indexed and 1024 resolution in steed of 256 x 256 8 bit and resolution 72 dpi . 

Makes a kick ass lookin skin with tons of detail . get on our server and really take a look in game at the new BS tribute skin i made . Detail is unreal compared to the stock skins . bright vivid colors and details . But is a trick to pull it off right . 

Main thing is all UT pcx or bmp is always indexed  or will not work in UT . change the image to RBG to work on it then back to Indexed before you import it into UT or Skin editor .