Ticket #1526: default-fallback-image.2.diff

wordcamp.org/public_html/wp-content/mu-plugins/jetpack-tweaks.php

@@ -12 +12 @@
 }
 add_filter( 'jetpack_open_graph_image_default', __NAMESPACE__ . '\default_og_image' );
 
+/**
+ * Open Graph Default Image for single posts, when no other image can be found in the post.
+ *
+ * 4 levels of fallback:
+ * - Site Logo -- http://jetpack.me/support/site-logo/
+ * - Site Icon -- https://make.wordpress.org/core/2015/07/27/site-icon/
+ * - Header Image -- https://codex.wordpress.org/Custom_Headers
+ * - Global default OG image -- See `jetpack_open_graph_image_default` filter above.
+ */
+function default_single_og_image( $media, $post_id, $args ) {
+        if ( $media ) {
+                return $media;
+        } else {
+
+                // First fallback, Site Logo, if the theme supports it and if the site owner uploaded a logo
+                if ( function_exists( 'jetpack_has_site_logo' ) && jetpack_has_site_logo() ) {
+                        $img_src = jetpack_get_site_logo( 'url' );
+                }
+
+                // Second fallback, Site Icon
+                if ( empty( $img_src ) && ( function_exists( 'has_site_icon') && has_site_icon() ) ) {
+                        $img_src = get_site_icon_url( null, '512' );
+                }
+
+                // Third fallback, Header image
+                if ( empty( $img_src ) && has_header_image() ) {
+                        $img_src = get_header_image();
+                }
+
+                // Fourth fallback, default image
+                if ( empty( $img_src ) ) {
+                        $img_src = apply_filters( 'jetpack_open_graph_image_default', 'https://s.w.org/images/backgrounds/wordpress-bg-medblue.png' );
+                }
+
+                return array( array(
+                        'type'  => 'image',
+                        'from'  => 'custom_fallback',
+                        'src'   => esc_url( $img_src ),
+                        'href'  => get_permalink( $post_id ),
+                ) );
+        }
+}
+add_filter( 'jetpack_images_get_images', 'default_single_og_image', 10, 3 );
+
+
 /*
  * Add Twitter Card type.
  *