function random_img1(num1,num2) {
    if((num1 - num2) > 0) {
      var big = num1
      var small = num2
    } else {
      var big = num2
      var small = num1
    }
  var range = big - small + 1
  var number = Math.floor(Math.random()*range) + small
  return(number)
  }

  function random_img2() {
    var img_src = "timg/img" + random_img1(1,22) + ".jpg"
    document.write("<IMG SRC='" + img_src + "'>")
  }