.things-gallery-wrap {
    background: #ddd;
    padding: 9px;
    margin: 30px 0px;
}
.things-gallery-item {
    margin: 10px;
    display: inline-block;
}

@media (max-width:1200px) {
    .things-gallery-item img { width: 120px; }
}
@media (max-width:800px) {
    .things-gallery-item img { width: 90px; }
}
@media (max-width:640px) {
    .things-gallery-item img { width: 60px; }
}