• To set up a background image, we should set it inside CSS file using url(...)
• By default, background image will repeat itself, you can set background-repeat to no-repeat, repeat-x (only repeat on horizontal axis), or repeat-y
• To strech the image to fit the whole screen, set background-size to 100% 100%, but also need to set height to 100wh
• You can also strech the image while keeping the aspect ratio by setting background-size to cover
• When you scroll the page, to let background image stay still, set background-attachment: fixed;

body {
  body {
    /* Provide image url */
    background: url(/images/[email protected]);
    /* no-repeat for the background img */
    background-repeat: no-repeat;
    /* let image fit entire screen */
    background-size: cover;
    /* Push the image 100px left, 100px down */
    background-position: 100px 100px;
    /* image stay fixed while scolling */
    background-attachment: fixed;
  }
}