#resImage_100 {
    display:block;
    overflow:hidden;
    background-image:url('https://www.conveyorrollers.co.uk/assets/images/a/polypropylene-roller-and-idlers-a92dc4b3.jpg');
    background-repeat:no-repeat;
    background-position:center center;
        width:100%;
    background-size: cover;
        height:380px;
}
@media screen and (min-width:700px){
    #resImage_100 {
        background-image:url('https://www.conveyorrollers.co.uk/assets/images/7/polypropylene-roller-and-idlers-9e130ef8.jpg');
                height:300px;
    }
}
@media screen and (min-width:980px){
    #resImage_100 {
        background-image:url('https://www.conveyorrollers.co.uk/assets/images/5/polypropylene-roller-and-idlers-4c723e2b.jpg');
                height:580px;
    }
}
@media screen and (min-width:1400px){
    #resImage_100 {
        background-image:url('https://www.conveyorrollers.co.uk/assets/images/9/polypropylene-roller-and-idlers-d27b43c8.jpg');
                height:580px;
    }
}