.photo {
  width: 100%;
  display: block;
  background-size: cover;
  background-position: center center;
  box-sizing: border-box;
}
.no-touch .photo {
  filter: url("data:image/svg+xml;utf8,<svg xmlns=\'http://www.w3.org/2000/svg\'><filter id=\'grayscale\'><feColorMatrix type=\'matrix\' values=\'0.3333 0.3333 0.3333 0 0 0.3333 0.3333 0.3333 0 0 0.3333 0.3333 0.3333 0 0 0 0 0 1 0\'/></filter></svg>#grayscale"); /* Firefox 10+, Firefox on Android */
  filter: gray; /* IE6-9 */
-webkit-filter: grayscale( 100% ); /* Chrome 19+, Safari 6+, Safari 6+ iOS */
  opacity: .7;
  transition: all 400ms ease-in-out;
}
.no-touch .photo:hover {
  filter: url("data:image/svg+xml;utf8,<svg xmlns=\'http://www.w3.org/2000/svg\'><filter id=\'grayscale\'><feColorMatrix type=\'matrix\' values=\'1 0 0 0 0, 0 1 0 0 0, 0 0 1 0 0, 0 0 0 1 0\'/></filter></svg>#grayscale");
-webkit-filter: grayscale(0%);
  opacity: 1;
}
.scrollable-div {
  height: 70vh; /* set a fixed height for the div */
  overflow-y: scroll; /* enable vertical scrollbar */
}
@media screen and ( min-width: 768px ) {
.photo { float: left; width: 50%; }
}
@media screen and ( min-width: 1023px ) {
.photo { width: 33.3333%; }
}
@media screen and ( min-width: 1220px ) {
.photo { width: 25%; }
}
@media screen and ( min-width: 1440px ) {
.photo { width: 20%; }
}

.photo:after {
  content: "";
  display: block;
  padding-bottom: 100%;
}