.facetwp-radio {
    background: url(../images/radio-off.png) no-repeat;
    margin-bottom: 4px;
    padding-left: 20px;
    cursor: pointer;
}

.facetwp-radio.selected {
    background: url(../images/radio-on.png) no-repeat;
}

.facetwp-radio.disabled {
    background: url(../images/radio-disabled.png) no-repeat;
}