おぼえがき

                  
.img_box01 {
    width: min(100%, 600px);
    margin: 0 auto;
    overflow: hidden;
}
.img_box01 img {
    width: 100%;
    height: auto;
    transform: scale(1.0);
    transition: transform .5s ease;
}
.img_box01:hover img {
    transform: scale(1.2);
}