Answers for "make a background image full screen css"

full page background image

html { 
  background: url(images/bg.jpg) no-repeat center center fixed; 
  -webkit-background-size: cover;
  -moz-background-size: cover;
  -o-background-size: cover;
  background-size: cover;
}

html background image fit to screen

body {
  background-position: center;
  background-repeat: no-repeat;
  background-size: contain;
}

how to cover full background with css

<div id="bg">
  <img src="images/bg.jpg" alt="">
</div>