html,
body {
  height: 100%;
  /*background-color: #333;*/
  background: url(../images/background3-20wopc.jpeg);
  background-repeat: no-repeat;
  background-size: cover;
  background-attachment: fixed;
}
body {
  padding-top: 5rem;
}

.starter-template {
  padding: 3rem 1.5rem;
  text-align: left;
}

iframe {
    max-width: 600px; /* or whatever */
    max-height: 300px; /* or whatever */
}

image {
    max-width: 600px; /* or whatever */
    max-height: 300px; /* or whatever */
}