diff --git a/wp-includes/class-wp-image-editor-gd.php b/wp-includes/class-wp-image-editor-gd.php
index c2105169ec..f175b90d20 100644
--- a/wp-includes/class-wp-image-editor-gd.php
+++ b/wp-includes/class-wp-image-editor-gd.php
@@ -423,13 +423,15 @@ class WP_Image_Editor_GD extends WP_Image_Editor {
 	 * Saves current in-memory image to file.
 	 *
 	 * @since 3.5.0
+	 * @since 5.9.0 Renamed `$filename` to `$destfilename` to match parent class
+	 *              for PHP 8 named parameter support.
 	 *
-	 * @param string|null $filename
-	 * @param string|null $mime_type
+	 * @param string|null $destfilename Optional. Destination filename. Default null.
+	 * @param string|null $mime_type    Optional. The mime-type. Default null.
 	 * @return array|WP_Error {'path'=>string, 'file'=>string, 'width'=>int, 'height'=>int, 'mime-type'=>string}
 	 */
-	public function save( $filename = null, $mime_type = null ) {
-		$saved = $this->_save( $this->image, $filename, $mime_type );
+	public function save( $destfilename = null, $mime_type = null ) {
+		$saved = $this->_save( $this->image, $destfilename, $mime_type );
 
 		if ( ! is_wp_error( $saved ) ) {
 			$this->file      = $saved['path'];
diff --git a/wp-includes/class-wp-image-editor-imagick.php b/wp-includes/class-wp-image-editor-imagick.php
index ae91e46970..b7336fe5ae 100644
--- a/wp-includes/class-wp-image-editor-imagick.php
+++ b/wp-includes/class-wp-image-editor-imagick.php
@@ -662,8 +662,8 @@ class WP_Image_Editor_Imagick extends WP_Image_Editor {
 	 *
 	 * @since 3.5.0
 	 *
-	 * @param string $destfilename
-	 * @param string $mime_type
+	 * @param string $destfilename Optional. Destination filename. Default null.
+	 * @param string $mime_type    Optional. The mime-type. Default null.
 	 * @return array|WP_Error {'path'=>string, 'file'=>string, 'width'=>int, 'height'=>int, 'mime-type'=>string}
 	 */
 	public function save( $destfilename = null, $mime_type = null ) {
diff --git a/wp-includes/class-wp-image-editor.php b/wp-includes/class-wp-image-editor.php
index a74d4ac743..b9e580c46f 100644
--- a/wp-includes/class-wp-image-editor.php
+++ b/wp-includes/class-wp-image-editor.php
@@ -77,8 +77,8 @@ abstract class WP_Image_Editor {
 	 * @since 3.5.0
 	 * @abstract
 	 *
-	 * @param string $destfilename
-	 * @param string $mime_type
+	 * @param string $destfilename Optional. Destination filename. Default null.
+	 * @param string $mime_type    Optional. The mime-type. Default null.
 	 * @return array|WP_Error {'path'=>string, 'file'=>string, 'width'=>int, 'height'=>int, 'mime-type'=>string}
 	 */
 	abstract public function save( $destfilename = null, $mime_type = null );
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 620192d557..bfa59a684a 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.9-alpha-51789';
+$wp_version = '5.9-alpha-51790';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.