Как наложить изображение на изображение?

<div class="icons">
  

<a href="" class="icon icon1">

  <svg aria-hidden="true" focusable="false" data-prefix="fab" data-icon="twitter" class="svg-inline--fa fa-twitter fa-w-16" role="img" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512" width="30" height="30"><path fill="currentColor" d="M459.37 151.716c.325 4.548.325 9.097.325 13.645 0 138.72-105.583 298.558-298.558 298.558-59.452 0-114.68-17.219-161.137-47.106 8.447.974 16.568 1.299 25.34 1.299 49.055 0 94.213-16.568 130.274-44.832-46.132-.975-84.792-31.188-98.112-72.772 6.498.974 12.995 1.624 19.818 1.624 9.421 0 18.843-1.3 27.614-3.573-48.081-9.747-84.143-51.98-84.143-102.985v-1.299c13.969 7.797 30.214 12.67 47.431 13.319-28.264-18.843-46.781-51.005-46.781-87.391 0-19.492 5.197-37.36 14.294-52.954 51.655 63.675 129.3 105.258 216.365 109.807-1.624-7.797-2.599-15.918-2.599-24.04 0-57.828 46.782-104.934 104.934-104.934 30.213 0 57.502 12.67 76.67 33.137 23.715-4.548 46.456-13.32 66.599-25.34-7.798 24.366-24.366 44.833-46.132 57.827 21.117-2.273 41.584-8.122 60.426-16.243-14.292 20.791-32.161 39.308-52.628 54.253z"></path></svg>

</a>
<a href="" class="icon icon2">

</a>

</div>

.icons {
  display: flex;
}

.icon{
  display: flex;
  justify-content: center;
  align-items: center;
  width: 50px;
  height: 50px;
  background: #eee;
  border-radius: 50%;
  color: red;
 
}
.icon1 {
  
}
.icon2 {
  background: #eee url("https://helinet.com/assets/images/social-twit.png") no-repeat center / 30px 30px;
}