From b3a582a8bba02a95979b452605bdd41fcb03d49a Mon Sep 17 00:00:00 2001
From: Matthias Pfefferle <pfefferle@users.noreply.github.com>
Date: Fri, 18 Sep 2026 19:09:32 +0200
Subject: [PATCH 1/2] summary card for fallback images

---
 opengraph.php                                | 13 +++++++++----
 tests/phpunit/tests/class-test-opengraph.php | 20 ++++++++++++++++++++
 2 files changed, 29 insertions(+), 4 deletions(-)

diff --git a/opengraph.php b/opengraph.php
index 35c56ae..70e5749 100644
--- a/opengraph.php
+++ b/opengraph.php
@@ -660,7 +660,8 @@ function opengraph_default_locale( $locale = '' ) {
  *
  * Twitter takes the image from `og:image`, so the card type only depends on
  * whether a singular post has one: `summary_large_image` if it does,
- * `summary` otherwise.
+ * `summary` otherwise. Fallback images (site icon, logo, header) are not
+ * the post's own images and look better in a small card.
  *
  * @param string $card     The current card type.
  * @param array  $metadata The metadata collected so far, including `og:image`.
@@ -672,11 +673,15 @@ function twitter_default_card( $card = '', $metadata = array() ) {
 		return $card;
 	}
 
-	if ( is_singular() && ! empty( $metadata['og:image'] ) ) {
-		return 'summary_large_image';
+	if ( ! is_singular() || empty( $metadata['og:image'] ) ) {
+		return 'summary';
 	}
 
-	return 'summary';
+	if ( opengraph_fallback_image() === $metadata['og:image'] ) {
+		return 'summary';
+	}
+
+	return 'summary_large_image';
 }
 
 
diff --git a/tests/phpunit/tests/class-test-opengraph.php b/tests/phpunit/tests/class-test-opengraph.php
index 5254aa3..faf12ca 100644
--- a/tests/phpunit/tests/class-test-opengraph.php
+++ b/tests/phpunit/tests/class-test-opengraph.php
@@ -158,6 +158,26 @@ public function test_twitter_card() {
 		$this->assertSame( 'summary_large_image', $metadata['twitter:card'] );
 	}
 
+	/**
+	 * Test the Twitter card stays small for fallback images.
+	 *
+	 * @covers ::twitter_default_card
+	 */
+	public function test_twitter_card_fallback_image() {
+		update_option( 'site_icon', $this->create_image() );
+
+		$post_id  = self::factory()->post->create();
+		$metadata = $this->metadata_for( get_permalink( $post_id ) );
+		$this->assertSame( array( get_site_icon_url( 512 ) ), $metadata['og:image'] );
+		$this->assertSame( 'summary', $metadata['twitter:card'] );
+
+		set_post_thumbnail( $post_id, $this->create_image() );
+		$metadata = $this->metadata_for( get_permalink( $post_id ) );
+		$this->assertSame( 'summary_large_image', $metadata['twitter:card'] );
+
+		delete_option( 'site_icon' );
+	}
+
 	/**
 	 * Test the property filters receive the metadata collected so far.
 	 *

From 4e24184448e8203c518ae3d86eba2f561f21f35d Mon Sep 17 00:00:00 2001
From: Matthias Pfefferle <pfefferle@users.noreply.github.com>
Date: Fri, 18 Sep 2026 19:14:42 +0200
Subject: [PATCH 2/2] more fallback tests

---
 tests/phpunit/tests/class-test-opengraph.php | 37 ++++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/tests/phpunit/tests/class-test-opengraph.php b/tests/phpunit/tests/class-test-opengraph.php
index faf12ca..5e1ec79 100644
--- a/tests/phpunit/tests/class-test-opengraph.php
+++ b/tests/phpunit/tests/class-test-opengraph.php
@@ -178,6 +178,43 @@ public function test_twitter_card_fallback_image() {
 		delete_option( 'site_icon' );
 	}
 
+	/**
+	 * Test the Twitter card stays small for the custom logo.
+	 *
+	 * @covers ::twitter_default_card
+	 */
+	public function test_twitter_card_fallback_custom_logo() {
+		set_theme_mod( 'custom_logo', $this->create_image() );
+
+		$post_id  = self::factory()->post->create();
+		$metadata = $this->metadata_for( get_permalink( $post_id ) );
+
+		remove_theme_mod( 'custom_logo' );
+
+		$this->assertCount( 1, $metadata['og:image'] );
+		$this->assertSame( 'summary', $metadata['twitter:card'] );
+	}
+
+	/**
+	 * Test the Twitter card stays small for random header images.
+	 *
+	 * @covers ::twitter_default_card
+	 */
+	public function test_twitter_card_fallback_random_header() {
+		foreach ( array( $this->create_image(), $this->create_image() ) as $header_id ) {
+			update_post_meta( $header_id, '_wp_attachment_is_custom_header', get_option( 'stylesheet' ) );
+		}
+		set_theme_mod( 'header_image', 'random-uploaded-image' );
+
+		$post_id  = self::factory()->post->create();
+		$metadata = $this->metadata_for( get_permalink( $post_id ) );
+
+		remove_theme_mod( 'header_image' );
+
+		$this->assertCount( 2, $metadata['og:image'] );
+		$this->assertSame( 'summary', $metadata['twitter:card'] );
+	}
+
 	/**
 	 * Test the property filters receive the metadata collected so far.
 	 *