.centeredImage{

    position: absolute;
    margin: auto;
    left: 0;
    right: 0;
    top: 0;
    bottom: 0;
}

body, html {
  height: 100%;
}

.bg {
  /* The image used */
  background-image: url("background.jpg");

  /* Full height */
  height: 100%;

  /* Center and scale the image nicely */
  background-position: center;
  background-repeat: no-repeat;
  background-size: cover;
}