input {

  /* sizing the button */

  width: 10em;

  height: 10em;

  /* disabling the system look */

  appearance: none;

  -webkit-appearance: none;

  /* resetting default browser styler */

  border: 0;

  margin: 0;

  padding: 0;

  /* hiding button label */

  text-indent: -9999px;

  /* applying the image */

  background: url('http://i.imgur.com/1x8TMLt.jpg') no-repeat transparent;

  background-size: 100% 100%; /* stretching */

  /* letting users know it's clickable */

  cursor: pointer;

}