#banner {
  background: url(../images/deck2.jpg);
}

.square {
  position: relative;
  width: 100%;
  padding-bottom: 100%;
  /* height = width */
  overflow: hidden;
  background: #f0f0f0;
  /* optional placeholder background */
}

.square img {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  /* crop as needed without distortion */
  object-position: center;
  /* center the image within the frame */
}

#gallery img {
  margin-top:15px;
}