SOURCE

<div class="container">
  <div class="box"></div>
</div>

.container{
  width: 200px;
  height: 200px;
  display:flex;
  justify-content:center;
  align-items:center;
}
.box{
  width: 200px;
  height: 200px;
  background: url(https://ss0.bdstatic.com/70cFvHSh_Q1YnxGkpoWK1HF6hhy/it/u=3685944947,3615220133&fm=27&gp=0.jpg) no-repeat center;
  transition:all .4s linear;
}
.container:hover .box{
  width: 100px;
  height: 100px;
  border-radius:50%;
}