function genRanNum()
{
  var min = 1;
  var max = 7;
  
  var random = min + Math.floor((max-min+1)*Math.random());
  
  return random;
}

function mainPic()
{
  document.write("<img src=\'media/" + genRanNum() + ".gif\'/>");
}

function resetImage()
{
  mainPic();
}