body.single-post .post-media img,
body.single-post .wp-post-image,
body.single-post .entry-thumbnail img,
body.single-post .thumbnail img {
    max-height: 500px !important;
    width: auto !important;
    margin-left: auto !important;
    margin-right: auto !important;
    display: block !important;
    border-radius: 8px;
}