<div class="bg">
  <img src="http://gwenduling.com/assets/gwe_baler.jpeg" alt="">
</div>

.bg {
  /* CREDITS TO THE OWNER OF THIS GIF I FOUND FROM A GOOGLE SEARCH */
  background-image: url("http://bestanimations.com/Nature/Water/wave-ocean-animated-gif-13.gif");
/*     background-image: url('https://media.giphy.com/media/LbBSU26sSRAE8/giphy.gif'); */
  background-size: cover;
  width: 100vw;
}

.bg img {
  width: 100%;

  mix-blend-mode: multiply;
}