Index: src/wp-admin/includes/class-wp-press-this.php
===================================================================
--- src/wp-admin/includes/class-wp-press-this.php	(revision 31694)
+++ src/wp-admin/includes/class-wp-press-this.php	(working copy)
@@ -388,7 +388,7 @@
 		} else if ( preg_match( '/\/pixel\.(mathtag|quantserve)\.com/', $src ) ) {
 			// See mathtag.com and https://www.quantcast.com/how-we-do-it/iab-standard-measurement/how-we-collect-data/
 			return '';
-		} else if ( false !== strpos( $src, '/g.gif' ) ) {
+		} else if ( preg_match( '/\/[gb]\.gif(\?.+)?$/', $src ) ) {
 			// Classic WP stats gif
 			return '';
 		}