body {
  background: #fff;
}
hr.style-eight {
    padding: 0;
    border: none;
    border-top: 3px solid #000;
    text-align: center;
    margin: 30px 0;
}
hr.style-eight:after {
    content: url(img);
    display: inline-block;
    position: relative;
    top: -25px;
    padding: 0px 0.25em;
    background: #fff; /* match this with body bg */
}