myPix = new Array("images/woods/wood__01.jpg", "images/woods/wood__02.jpg", "images/woods/wood__03.jpg", "images/woods/wood__04.jpg", "images/woods/wood__05.jpg", "images/woods/wood__06.jpg", "images/woods/wood__07.jpg", "images/woods/wood__08.jpg", "images/woods/wood__09.jpg"," images/woods/wood__10.jpg", "images/woods/wood__11.jpg","images/woods/wood__12.jpg","images/woods/wood__13.jpg")

imgCt = myPix.length

function choosePic() {
   if (document.images) {
      randomNum = Math.floor
      ((Math.random() * imgCt))
      document.myPicture.src = myPix[randomNum]
   }
}