index.css

.example {
  display: block;
  vertical-align: top;
  text-align: center;
  padding: 1em;
}
.example img {
  margin-bottom: 1em;
  max-width: 100%;
}
article figure img {
  max-width: 100%;
}

#photos-grid {
  /* Prevent vertical gaps */
  line-height: 0;
  -moz-column-count: 5;
  -moz-column-gap: 0px;
  column-count: 5;
  column-gap: 0px;
}

#photos-grid img {
  /* Just in case there are inline attributes */
  width: 100% !important;
  height: auto !important;
}

img[ix-sizes='auto'] {
  display: block;
  width: 100%;
}

.size-info {
  z-index: 1;
  position: relative;
  bottom: 40px;
  color: white;
  font-size: x-large;
  background-color: black;
  width: auto;
  height: auto;
}

.size-info p {
  text-align: right;
}

/* media queries test the browser width and adjust
  the number of columns accordingly. */

@media (max-width: 1200px) {
  #photos-grid {
    -moz-column-count: 4;
    column-count: 4;
  }
}
@media (max-width: 1000px) {
  #photos-grid {
    -moz-column-count: 3;
    column-count: 3;
  }
}
@media (max-width: 800px) {
  #photos-grid {
    -moz-column-count: 2;
    column-count: 2;
  }
}
@media (max-width: 400px) {
  #photos-grid {
    -moz-column-count: 1;
    column-count: 1;
  }
}