body {
    background-image: url('images/background.png');
    background-repeat: repeat;       /* repeats both horizontally and vertically */
    background-position: top left;   /* optional: start position */
    background-size: auto;           /* keeps original size */
}

img {
  max-width: 100%;
  height: auto;
  display: block;
  margin: 0.5em 0;
}