Alert: This function’s access is marked private. This means it is not intended for use by plugin or theme developers, only in other core functions. It is listed here for completeness.

_wp_check_existing_file_names( string $filename, array $files )

Helper function to check if a file name could match an existing image sub-size file name.

Parameters Parameters


(string) (Required) The file name to check.


(array) (Required) An array of existing files in the directory.

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Return Return

(bool) True if the tested file name could match an existing file, false otherwise.

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Source Source

File: wp-includes/functions.php

function _wp_check_existing_file_names( $filename, $files ) {
	$fname = pathinfo( $filename, PATHINFO_FILENAME );
	$ext   = pathinfo( $filename, PATHINFO_EXTENSION );

	// Edge case, file names like `.ext`.
	if ( empty( $fname ) ) {
		return false;

	if ( $ext ) {
		$ext = ".$ext";

	$regex = '/^' . preg_quote( $fname ) . '-(?:\d+x\d+|scaled|rotated)' . preg_quote( $ext ) . '$/i';

	foreach ( $files as $file ) {
		if ( preg_match( $regex, $file ) ) {
			return true;

	return false;

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Changelog Changelog

Version Description
5.3.1 Introduced.

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