<style>.centeredImage {
  position: fixed;
  top: 50%;
  left: 50%;
  margin-top: -50px;
  margin-left: -150px;
}
</style>
<div img class="centeredImage" src="https://cdn.pixabay.com/photo/2013/07/12/12/58/tv-test-pattern-146649_1280.png"></div>