if(!empty($_POST['img_filter'])) {
        $source = __DIR__.'/MIW 600/'.$_POST['img_filter'].'.jpg';
        echo $source;
    }

jQuery("#filter_number").on("keyup", function () {
        var d = jQuery("#filter_number").val();
        if(d != null && d != '') {
            jQuery.ajax({
                type: "POST",
                url: ajax_object.ajaxurl,
                data: {
                    'action': 'ajax_object',
                    'img_filter': d
                },
                success: function (data) {
                    jQuery("#drawing").attr('src', data);
                    console.log(data);
                }
            });
        }
    });

Not allowed to load local resource: file:///C:/OpenServer/domains/wordpress-test/wp-content/plugins/oil-filters/MIW%20600/H1013.jpg`