.grid-phototheque{
    display: grid;
    grid-gap: 10px;
    grid-template-columns: repeat(4, 1fr);
}

.grid-phototheque img{
    max-width: 100%;
}


@media screen and  (max-width: 992px) {
    .grid-phototheque{
        grid-template-columns: repeat(2, 1fr);
    }
}