Post Images: don't fetch Gravatars from post content (#38692)

Fixes #38501

projects/plugins/jetpack/changelog/update-post-images-gravatar

@@ -0,0 +1,4 @@
+Significance: patch
+Type: bugfix
+
+Sharing: do not include Gravatar images in Open Graph Meta tags.

projects/plugins/jetpack/class.jetpack-post-images.php

@@ -515,6 +515,12 @@ public static function from_html( $html_or_id, $width = 200, $height = 200 ) {
 			if ( stripos( $img_src, '/smilies/' ) ) {
 				continue;
 			}
+
+			// Do not grab Gravatar images.
+			if ( stripos( $img_src, 'gravatar.com' ) ) {
+				continue;
+			}
+
 			// First try to get the width and height from the img attributes, but if they are not set, check to see if they are specified in the url. WordPress automatically names files like foo-1024x768.jpg during the upload process
 			$width  = (int) $image_tag->getAttribute( 'width' );
 			$height = (int) $image_tag->getAttribute( 'height' );

projects/plugins/jetpack/tests/php/media/test-class.jetpack-post-images.php

@@ -40,6 +40,20 @@ public function test_from_html_double_quotes() {
 		$this->assertEquals( 200, $result[0]['src_height'] );
 	}
 
+	/**
+	 * Ensure that Gravatar images are not included in the list of images extracted from the post contents (html).
+	 *
+	 * @since $$next-version$$
+	 */
+	public function test_from_html_gravatar() {
+		$s = '<img class="jetpack-blogging-prompt__answers-gravatar wp-hovercard-attachment grav-hashed grav-hijack" aria-hidden="true" src="https://0.gravatar.com/avatar/89f071d1932fe8c204a3381e00bd6794ddc28bcdb0642f29c9f48beaa5e277af?s=96&d=identicon&r=G">';
+
+		$result = Jetpack_PostImages::from_html( $s );
+
+		$this->assertIsArray( $result );
+		$this->assertEmpty( $result );
+	}
+
 	/**
 	 * Test image size extract in src filename
 	 *