.bigbox {
margin: auto 0;text-align: center;BACKGROUND-COLOR: #988;
 }



.bigbox img{
    max-width: 80%;MARGIN: AUTO;
}

@media only screen and (max-width: 768px) {
    /* For mobile phones: */

    .bigbox img{
        WIDTH: 100%;MARGIN: AUTO; max-width:100%
    }

}