.testimonial-bg {
    background: url('https://drive.google.com/thumbnail?id=1MCSp4cB3XKYcUE_vMq-3lors0-7asr--&sz=w1000') no-repeat; 
}

.bg-testimonial::after {
    height: 55%;
    left: 0;
    top: 0;
    position: absolute;
    background: url('https://drive.google.com/thumbnail?id=1MCSp4cB3XKYcUE_vMq-3lors0-7asr--&sz=w1000') no-repeat center center;
    -webkit-background-size: cover;
    background-size: cover;
    z-index: -1;
}