var numimg = 7;
  var addbegin1 = "/images/red_0";
  var addbegin2 = "/images/grey_0";
  var addbegin3 = "/images/green_0";
  var addbegin = "/images/blue_large_0";
  var addend = ".jpg"

  function randimg() {
   num = (rnd() * 10) + 1
   num = parseInt(num)

   if (num > numimg) { num = numimg; }
   if (num < 1) { num = 1 }
   numstr = num + "";
   numimgstr = numimg + "";

  document.imgblue.src = addbegin + numstr + addend
  document.imgpublic.src = addbegin1 + numstr + addend;
  document.imgmembers.src = addbegin2 + numstr + addend;
  document.imgsponsors.src = addbegin3 + numstr + addend;
 }

  function rnd() {
   return Math.random()
  }