img {
    display: block;
    margin: auto;
  width: 32%;
  height: 32%;
  background-color: grey;

}

.caption {
    /* Make the caption a block so it occupies its own line. */
    display: block;
    text-align: center;
    font-family: Helvetica;
    font-weight: bold;
    font-size: 50px;
    letter-spacing: -0.5px;
    margin-top: 20px;

}