@media(min-width: 768px) and (max-width: 991px){
    .navbar{
    background-image: url(TopHeader_960x120.png);
    height: 120px;
    }

}
@media(min-width: 992px) and (max-width: 1169px){
    .navbar{
    background-image: url(TopHeader_992x124.png);
    height: 124px;
    }

}
@media(min-width: 1170px){
    .navbar{
    background-image: url(TopHeader_1170x146.png);
    height: 146px;
    }
}