michelep/header.php

## header.php
In header.php theme file, add this between <head> and </head> tags:

<?php
if ( is_single() && 'post' == get_post_type() ) {
	if(has_post_thumbnail($post->ID)) {
            $img_src = wp_get_attachment_url( get_post_thumbnail_id($post->ID) );
        }
        if($excerpt = get_the_excerpt()) {
            $excerpt = strip_tags($excerpt);
            $excerpt = str_replace("", "'", $excerpt);
        } else {
            $excerpt = get_bloginfo('description');
        }
?>
<!-- OpenGraph meta for social -->
	<meta property="og:title" content="<?php the_title(); ?>" />
	<meta property="og:type" content="article" />
	<meta property="og:image" content="<?php echo $img_src; ?>" />
	<meta property="og:url" content="<?php the_permalink(); ?>" />
	<meta property="og:description" content="<?php echo $excerpt; ?>" />
	<meta property="og:site_name" content="<?php echo get_bloginfo(); ?>"/>
	<meta name="twitter:card" content="summary_large_image" />
	<meta name="twitter:site" content="@[twitter username]" />
<?php
}
?>