.single-post .blog-post img {

display: block;
max-width: 100%;
height: auto;
}

.cd-image {
    padding-top: 140%;
    background-size: cover;
    background-position: center;
}


div.img-responsive {
    padding-top: 130%;
    background-size: cover;
    background-position: center;
}

.center-block.footer-ad-image{
  max-width: 300px;
}