* {
    box-sizing: border-box;
}

.responsive {
    float: left;
    width: 25%;
}

img {
    width: 99%;
    height: 50vh;
    object-fit: cover
}

@media only screen and (max-width: 768px) {
    .responsive {
      width: 50%;
    }
}

@media only screen and (max-width: 540px) {
    .responsive {
      width: 100%;
    }
}