How To Set Perfect Full Page Background Image

To Set perfect background picture, which is centered and works on cross browser platform you have to use :

Technique #1 :

img.bg {
  /* Set rules to fill background */
  min-height: 100%;
  min-width: 1024px;
	
  /* Set up proportionate scaling */
  width: 100%;
  height: auto;
	
  /* Set up positioning */
  position: fixed;
  top: 0;
  left: 0;
}

@media screen and (max-width: 1024px) { /* Specific to this particular image */
  img.bg {
    left: 50%;
    margin-left: -512px;   /* 50% */
  }

Technique #2 :


#bg {
  position: fixed; 
  top: 0; 
  left: 0; 
	
  /* Preserve aspet ratio */
  min-width: 100%;
  min-height: 100%;
}