JSFiddle - React, Tailwind, and code Playground

HTML

<div class="owl-item" style="width: 465px;">
  <a class="img-flux" href="page1.html">
    <img alt="omg" src="http://placehold.it/1000x100">
  </a>
</div>

<div class="owl-item" style="width: 465px;">
  <a class="img-flux" href="page1.html">
    <img alt="omg" src="http://placehold.it/400x780">
  </a>
</div>

CSS

.img-flux img {
    border: 0;
    max-height: 100%;
    max-width: 100%;
    height: auto;
    width: auto;
    position: relative;
    transition: all 0.3s;
    margin: 0 auto;
    float: none;
    display: block;
    vertical-align:middle;
}
#content-block *:last-child {
    margin-bottom: 0px;
}
.owl-item, .owl-item .img-flux {
    height: 100%;
}
.img-flux {
    background-color: #ECECEC;
    position: relative;
    width: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
    overflow: hidden;
}
.owl-item{
  float:left;
  height:300px;
  margin-bottom:50px;
}