.square-512{
    width: 100%;
    aspect-ratio: 1 / 1;     /* keeps it square */
    overflow: hidden;
    border-radius: 12px;     /* optional */
}

.square-512 img{
    width: 100%;
    height: 100%;
    object-fit: cover;       /* fills square without distortion */
    display: block;
}