.img_with_caption {
    width: 620px;
    margin: 0 auto;
}

#d {
    display:block;
    max-width: 620px;
    max-height: 620px;
}

p {
    font-family: 'Roboto', 'sans-serif';
    background: #eee;
    color: #777;
    font-size: 13px;
    height: auto;
    margin: 0 auto;
    padding: 10px 14px 10px;
    line-height: 18px;
}




@media only screen and (max-width:500px) {

    .img_with_caption {
        width: 300px;
    }

    #d {
        display:block;
        max-width: 300px;
        max-height: 300px;
    }


}