.flag {
  width: 16px;
  height: 11px;
  display:inline-block;
  background:url(../img/flags.png) no-repeat
}

.flag.flag-de {background-position: -16px 0}
.flag.flag-fr {background-position: 0 -11px}
.flag.flag-en {background-position: -16px -11px}