// random number
function randomNumber(limit){
  return Math.floor(Math.random()*limit);
}

// display random images
function randomImage(imgArr)
{
  var imgSrc, imgW, imgH, r;
  r = randomNumber(imgArr.length / 3);
  
  imgSrc = imgArr[r * 3];
  imgW = imgArr[(r * 3)+1];
  imgH = imgArr[(r * 3)+2];

  document.write('<IMG SRC='+imgSrc+' WIDTH='+imgW+' HEIGHT='+imgH+'>');
}

function randomIndexImage(imgArr)
{
  var imgSrc, imgW, imgH, imgAlign, r;
  r = randomNumber(imgArr.length / 4);
  
  imgSrc = imgArr[r * 4];
  imgW = imgArr[(r * 4)+1];
  imgH = imgArr[(r * 4)+2];
  imgAlign = imgArr[(r * 4)+3];

  document.write('<IMG SRC='+imgSrc+' WIDTH='+imgW+' HEIGHT='+imgH+' ALIGN='+imgAlign+'>');
}