.photo-gallery-grid {
 margin: 0 -2px 30px;
 list-style: none;
 padding: 0;
}
.photo-gallery-grid li {
  display: block;
  float: left;
  padding: 2px;
}
@media (max-width: 767px) {
  .photo-gallery-grid li {
    width: 33.333%;
  }
}
@media (min-width: 768px) {
  .photo-gallery-grid li {
    width: 25%;
  }
}
.photo-gallery-grid a {
  display: block;
}
.photo-gallery-grid img {
  display: block;
  width: 100%;
  max-width: 100%;
}