Facebook Wordpress plugin temporary fix. This fixes issue where https://www.facebook.com/sharer/sharer.php throws "The message could not be posted to this Wall." when there are multiple "og:image" meta tag.

open-graph-protocol.php

	/**
	 * Identify image attachments related to the post.
	 *
	 * Request the full size of the attachment, not necessarily the same as the size used in the post.
	 *
	 * @since 1.5
	 *
	 * @param stdClass|WP_Post $post WordPress post of interest
	 * @return array {
	 *     Open Graph protocol image structured data
	 *
	 *     @type string URL of the image
	 *     @type array associative array of image data
	 * }
	 */
	public static function get_og_images( $post ) {
		$og_images = array();

		if ( ! $post || ! isset( $post->ID ) )
			return $og_images;

		// does current post type and the current theme support post thumbnails?
		if ( post_type_supports( get_post_type( $post ), 'thumbnail' ) && function_exists( 'has_post_thumbnail' ) && has_post_thumbnail() ) {
			list( $post_thumbnail_url, $post_thumbnail_width, $post_thumbnail_height ) = wp_get_attachment_image_src( get_post_thumbnail_id( $post->ID ), 'full' );

			$image = self::attachment_to_og_image( get_post_thumbnail_id( $post->ID ) );
			if ( isset( $image['url'] ) && ! isset( $og_images[ $image['url'] ] ) )
				$og_images[ $image['url'] ] = $image;
			unset( $image );
		}
        
		// get image attachments
		if ( function_exists( 'get_attached_media' ) ) {
			$images = get_attached_media( 'image', $post->ID );
			if ( ! empty( $images ) ) {
              
                if (count( $og_images ) === 1) {
                    return $og_images; // Force only 1 image.
                }
                    
				foreach( $images as $i ) {
					if ( ! isset( $i->ID ) )
						continue;

					$image = self::attachment_to_og_image( $i->ID );
					if ( ! isset( $image['url'] ) || isset( $og_images[ $image['url'] ] ) )
						continue;

					$og_images[ $image['url'] ] = $image;
					if ( count( $og_images ) === self::MAX_IMAGE_COUNT )
						return $og_images;
                    
				}
			}
			unset( $images );
		}

		// test for WP_Embed handled images
		if ( ! empty( $post->post_content ) ) {
			// Instagram
			preg_match_all( '#\s*http://instagr(\.am|am\.com)/p/(.*)/\s*#i', $post->post_content, $matches );
			if ( isset( $matches[2] ) ) {
				foreach( $matches[2] as $instagram_id ) {
					$instagram_url = esc_url_raw( 'http://instagram.com/p/' . $instagram_id . '/media/?size=l', array( 'http' ) );
					if ( ! $instagram_url || isset( $og_images[$instagram_url] ) )
						continue;
					$og_images[$instagram_url] = array( 'url' => $instagram_url );
					unset( $instagram_url );
				}
			}
			unset( $matches );
		}

		// add gallery content
		if ( function_exists( 'get_post_galleries' ) ) {
			// use get_post_galleries function from WP 3.6+
			$galleries = get_post_galleries( $post, false );
			foreach( $galleries as $gallery ) {
				// use ids to request full-size image URI
				if ( ! ( isset( $gallery['ids'] ) && $gallery['ids'] ) )
					continue;

				$gallery['ids'] = explode( ',', $gallery['ids'] );
				foreach( $gallery['ids'] as $attachment_id ) {
					$image = self::attachment_to_og_image( $attachment_id );
					if ( ! isset( $image['url'] ) || isset( $og_images[ $image['url'] ] ) )
						continue;

					$og_images[ $image['url'] ] = $image;
					if ( count( $og_images ) === self::MAX_IMAGE_COUNT )
						return $og_images;

					unset( $image );
				}
			}
			unset( $galleries );
		} else {
			// extract full-size images from gallery shortcode
			$og_images = self::gallery_images( $post, $og_images );
		}

		return $og_images;
	}