Allows to skip image files have particular search term in the filename

skip_smush_filename_basis.php

<?php
/**
 * @package WP Smush
 */
/*
Plugin Name: Smush - Skip Landing Page Images
Plugin URI: https://wordpress.org/plugins/wp-smushit/
Description: This allows you to skip images from smushing with name containing a string e.g. `landing_page`
Author: Umesh Kumar
Version: 1.0
Author URI: https://profiles.wordpress.org/umeshsingla
*/

//You'd need to add `landing_page` or a similar term to all the images you'd like to skip. Make sure to update the code in here
//according to the modification you make.
add_filter( 'wp_smush_image', 'skip_landing_page_images', '', 2 );
if( !function_exists('skip_landing_page_images') ) {
	/**
	 * Skip a file from smushing based on matching search pattern in file name
	 *
	 * @param $smush
	 * @param $id
	 *
	 * @return bool
	 */
	function skip_landing_page_images( $smush, $id ) {
		//If we don't have attachment id
		if ( empty( $id ) ) {
			return $smush;
		}
		//Get the File name
		$file_name = get_attached_file( $id );
		if ( empty( $file_name ) ) {
			return $smush;
		}
		//Check for a particular search term in the file name
		if ( strpos( $file_name, 'landing_page' ) !== false ) {
			return false;
		}

		return $smush;
	}
}