.img-gallery {
    display: flex;
    flex-wrap: wrap;
    margin-bottom: 8vw;
}
.img-gallery .single-image {
    width: calc(25% - 4vw);
    min-width: 180px;
    margin: 0 2vw 1vw 2vw;
}
.img-gallery .single-image img {
    width: 100%;
}

@media screen and (max-width: 1280px) and (min-width: 768px) {
    .img-gallery .single-image {
        width: calc(50% - 4vw);
        min-width: 180px;
        margin: 0 2vw;
    }
}
@media screen and (max-width: 768px) {
    .img-gallery .single-image {
        width: calc(100% - 4vw);
        min-width: 180px;
        margin: 0 2vw;
    }
}