Opengraph thumbnails

gistfile1.aw

In WP functions.php:

function get_post_id() { global $wp_query; $id = $wp_query->post->ID; return $id; }

function opengraph_thumbnail(){
	if (is_single()) {
		echo get_the_post_thumbnail(get_post_id());
	} else {
		echo imagedir() ?>/about_better.png <?php ;
	}
}

In WP header.php:

<meta property="og:image" content="<?php opengraph_thumbnail(); ?>" />

Output is this:

<meta property="og:image" content="" />

:(

Try this:

function get_post_id() { 
    global $wp_query; 
    $id = $wp_query->post->ID; 
    return $id; 
}

function opengraph_thumbnail(){
        $id = get_post_id();
    if (is_single() && has_post_thumbnail($id) !== FALSE) { 
        $image = wp_get_attachment_image_src( get_post_thumbnail_id( $id ), 'single-post-thumbnail' );
        echo $image[0];
    } else {
        echo imagedir() ?>/about_better.png <?php ;
    }
}