WordPress Francophone

<?php
	// Set complete url of default website image, ex: your logo
	$default_img = '[url]';
?>
<?php 
	// Verify page type, single post or single page
	// Or print HTML code with default website image
	if(is_single() || is_page()): ?>
	<?php 
		// Get attachments for this post / page
		$args = array( 'post_type' => 'attachment', 'post_parent'=> $post->ID);
		$myposts = get_posts( $args );
	?>
	<!-- Add default image -->
	<meta property="og:image" content="<?php echo $default_img; ?>" />
	<link rel="image_src" type="image/jpeg" href="<?php echo $default_img; ?>" />
	<!-- Listing of posts -->
	<?php foreach ($myposts as $key): ?>
		<?php 
			// Verify if attachment is an image and not an other type
			// Print HTML code 
			if (preg_match("/^image/", $key->post_mime_type)): ?>
				<meta property="og:image" content="<?php echo $key->guid; ?>" />
				<link rel="image_src" type="image/jpeg" href="<?php echo $key->guid; ?>" />
		<?php endif; ?>
	<?php endforeach; ?>
<?php else: ?>
	<meta property="og:image" content="<?php echo $default_img; ?>" />
	<link rel="image_src" type="image/jpeg" href="<?php echo $default_img; ?>" />
<?php endif; ?>