#sec1 > img {
    width: 250px;
    height: 250px;

    border-radius: 10px;
    margin: 20px;
}

#sec2 {
    margin-top: 20px;
}

#sec2 > img {
    width: 80px;
    height: 80px;

    margin: 4px;
    box-sizing: border-box;
}

#sec2 > img:hover {
    border: 3px solid blue;
}