CSS Skins for gmod and css skin glitches

Recently I have been downloading css skins from fps banana and putting it in my gmod folder instead of my css folder.The skins work but some skins i download have black spots or dents in them.Like in the picture of this download http://www.fpsbanana.com/skins/17596 I looked at the picture and it had no problems or anything.But when i went into gmod the top part was all black just plain black.It happened on my css skins in css too.I had this tar skin and then days or weeks later most of it turned black.I know its not because of gmod its because of some update or something.Someone please explain Thx.can like someone reply cause my last post got no reply

sounds like a computer error, dont know if its hardware or software related, try updating your graphics drivers, some people say to pu -dxlevel 80 in launch options, try that too, worked when bloob was basically black dents