Index: wp-admin/includes/class-pclzip.php
===================================================================
--- wp-admin/includes/class-pclzip.php	(revision 55754)
+++ wp-admin/includes/class-pclzip.php	(working copy)
@@ -1170,8 +1170,8 @@
     // ----- Reset the error handler
     $this->privErrorReset();
 
-    // ----- Look if the $p_archive is a PclZip object
-    if (is_object($p_archive) && $p_archive instanceof pclzip)
+    // ----- Look if the $p_archive is an instantiated PclZip object
+    if ($p_archive instanceof pclzip)
     {
 
       // ----- Duplicate the archive
@@ -1234,8 +1234,8 @@
       return(0);
     }
 
-    // ----- Look if the $p_archive_to_add is a PclZip object
-    if (is_object($p_archive_to_add) && $p_archive_to_add instanceof pclzip)
+    // ----- Look if the $p_archive_to_add is an instantiated PclZip object
+    if ($p_archive_to_add instanceof pclzip)
     {
 
       // ----- Merge the archive
Index: wp-includes/media.php
===================================================================
--- wp-includes/media.php	(revision 55754)
+++ wp-includes/media.php	(working copy)
@@ -3759,7 +3759,7 @@
  */
 function is_gd_image( $image ) {
 	if ( is_resource( $image ) && 'gd' === get_resource_type( $image )
-		|| is_object( $image ) && $image instanceof GdImage
+		|| $image instanceof GdImage
 	) {
 		return true;
 	}