.leaflet-control-liveupdate a {
  background:#fff url(liveupdate.png) no-repeat 2px 2px;
  background-size:26px 52px;
}
.leaflet-liveupdate-on .leaflet-control-liveupdate a {
    background-position:2px -24px;
}
.leaflet-liveupdate-on a {
    background-position:2px -24px;
}