WordPress Image Embed

post-embed.php

public function embedWrapper($html, $url, $attr)
{
    $classes = ['post-embed'];
    if (strpos($url, 'youtu.be') !== false || strpos($url, 'youtube.com') !== false || strpos($url, 'vimeo') !== false) {
        $classes[] = 'post-embed--video';
    } else if (strpos($url, 'twitter.com') !== false) {
        $classes[] = 'post-embed--twitter';
    }
    $classes = implode(' ', $classes);
    return '<figure class="' . $classes . '">' . $html . '</figure>';
}
add_filter('embed_oembed_html', 'embedWrapper', 10, 3);



.post-embed {
    margin: 24px 0;
}

.post-embed--video {
    position: relative;
    padding-top: calc(100% * 9/16);
}

.post-embed--video iframe,
.post-embed--video object {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
}

.post-embed--twitter {
    margin-left: auto;
    margin-right: auto;
    max-width: 500px;
    background-color: #fff;
}