title: Change Size of Javascript Background Image
body: <p>I have a Javascript that randomly picks a new background image. </p>
  
  <pre><code>&lt;script  type="text/javascript"&gt;
      function changeImg(imgNumber)   {
          var myImages = ["images/001.jpg", "images/002.jpg", "images/003.jpg",      "images/004.jpg"]; 
          var imgShown = document.body.style.backgroundImage;
          var newImgNumber =Math.floor(Math.random()*myImages.length);
          document.body.style.backgroundImage =      'url('+myImages[newImgNumber]+')';
      }
      window.onload=changeImg;
      &lt;/script&gt;
  </code></pre>
  
  <p>I want to know how to resize that image. 
  Also, I want to know how to make the image not stay fixed to the page, but scroll along with the page normally.</p>