attachments plugin method add

attachments.php

<?php
define('ATTACHMENTS_SETTINGS_SCREEN', false);
add_filter('attachments_default_instance', '__return_false');

// field area
function philosophy_attachments($attachments){
    // if else
    $post_id = null;
    if( isset( $_REQUEST['post']) || isset( $_REQUEST['post_ID'] ) ){
        $post_id = empty($_REQUEST['post_ID']) ? $_REQUEST['post'] : $_REQUEST['post_ID'];
    }
    if(!$post_id || get_post_format( $post_id )!="gallery"){
        return;
    }

    $fields = array(
        array(
            'name'  => 'title',
            'type'  => 'text',
            'label' => __('Title', 'philosophy'),
        ),
    );

// add area
    $args = array(
        'label'     =>  'Gallery',
        'post_type' =>   array('post'),
        'filetype'  =>   array("image"),
        'note'      =>   'Add Gallery Images',
        'button_text'   => __('Attach Image', 'philosophy'),
        'fields'        => $fields,
    );
// add slider
    $attachments->register('gallery', $args);
}
add_action('attachments_register', 'philosophy_attachments');