@media screen and ( min-width: 960px ) {
    #videoIntroThumb {
        width: 150px;
    }
}

@media screen and (min-width: 480px) and (max-width: 959px) {
    #videoIntroThumb {
        width: 100px;
    }
}

@media screen and (max-width: 479px){
    #videoIntroThumb {
        width: 100px;
    }
}