Static background picture using a div

Goal: use a picture backgroud that will work realy nicely.
1. We need some HTML to put the picture in. Make sure your code is at the top of your page.
<div id="bg">
    <img src="yourpicture.jpg" alt="">
</div>
2. We use a little css to make it work.
#bg {
  position: fixed; 
  top: -50%; 
  left: -50%; 
  width: 200%; 
  height: 200%;
}
#bg img {
  position: absolute; 
  top: 0; 
  left: 0; 
  right: 0; 
  bottom: 0; 
  margin: auto; 
  min-width: 50%;
  min-height: 50%;
}