body {
  margin: 0;
  padding: 0;
  background-color: #f2f2f2;
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
}

.img-desktop {
  display: block;
  max-width: 100%;
  height: auto;
}

.img-mobile {
  display: none;
}

@media only screen and (max-width: 768px) {
  .img-desktop {
    display: none;
  }

  .img-mobile {
    display: block;
    max-width: 100%;
    height: auto;
  }
}