function query_vars($public_query_vars) {
    $public_query_vars[] = "imagem";
    $public_query_vars[] = "id";
    $public_query_vars[] = "w";
    $public_query_vars[] = "h";
    $public_query_vars[] = "m";
    return $public_query_vars;
    }
    add_filter('query_vars', 'query_vars');

    function add_rewrite_rules( $wp_rewrite ){
    $new_rules = array();
    $new_rules['imagem/(.*)_(.*)x(.*)_(.*).jpg'] = 'index.php?imagem=true'.
                                                             '&id='.$wp_rewrite->preg_index(1).
                                                             '&w='.$wp_rewrite->preg_index(2).
                                                             '&h='.$wp_rewrite->preg_index(3).
                                                             '&m='.$wp_rewrite->preg_index(4);
    $wp_rewrite->rules = $new_rules + $wp_rewrite->rules;
    }
    add_action('generate_rewrite_rules', 'add_rewrite_rules');


    function template_redirect_intercept() {
    if (get_query_var('imagem')) {
        $id = get_query_var('id');
        $w = get_query_var('w');
        $h = get_query_var('h');
        switch (get_query_var('m')) {
            case 1:
                $m = 'crop';
                break;
        }
        include ('getImage2.php'); // my class
        exit;
    }
    }
    add_action( 'template_redirect', 'template_redirect_intercept' );