body {
  font-family: Arial, Helvetica, sans-serif;
}

img {
  width: 100%;
  height: auto;
}


@media (min-width: 25em) {
  img {
    width: 50%;
    float: right;
    margin: 0 0 1em 1em;
  }
}

@media (min-width: 50em) {
  img {
    width: 25%;
  }
}