_copy_image_file() WordPress Function

function _copy_image_file( $attachment_id ) {
	$dst_file = get_attached_file( $attachment_id );
	$src_file = $dst_file;

	if ( ! file_exists( $src_file ) ) {
		$src_file = _load_image_to_edit_path( $attachment_id );
	}

	if ( $src_file ) {
		$dst_file = str_replace( wp_basename( $dst_file ), 'copy-' . wp_basename( $dst_file ), $dst_file );
		$dst_file = dirname( $dst_file ) . '/' . wp_unique_filename( dirname( $dst_file ), wp_basename( $dst_file ) );

		/*
		 * The directory containing the original file may no longer
		 * exist when using a replication plugin.
		 */
		wp_mkdir_p( dirname( $dst_file ) );

		if ( ! copy( $src_file, $dst_file ) ) {
			$dst_file = false;
		}
	} else {
		$dst_file = false;
	}

	return $dst_file;
}
Uses	Description
wp-admin/includes/image.php:_load_image_to_edit_path()	Retrieve the path or URL of an attachment’s attached file.
wp-includes/formatting.php:wp_basename()	i18n-friendly version of basename().
wp-includes/functions.php:wp_unique_filename()	Get a filename that is sanitized and unique for the given directory.
wp-includes/functions.php:wp_mkdir_p()	Recursive directory creation based on full path.
wp-includes/post.php:get_attached_file()	Retrieve attached file path based on attachment ID.