Trying to put info from files into database

ok atm I am not too bothered about the width and height then.  I have tried the following but I am getting an "Invalid argument supplied for foreach()"

PHP Code:

$this->db->truncate('gallery_images');

    $this->load->helper('directory');
    $this->load->helper('file');
    
    $files = directory_map(base_url().'public/images/gallery/');
    
    foreach($files as $file) {
        
        $get_info = get_file_info($file);
        
        $data = array( 
            'category' => 'uncategorised',
            'image_name' => $get_info['name'],
            'alt' => $get_info['name'],
            'full_path' => $get_info['server_path'],
            'image_width' => '800',
            'image_height' => '600'
        );
        $this->add_content($data, 'gallery_images');

    }
    $this->session->set_flashdata('success_message', 'Gallery Reloaded');
    redirect('admin/gallery/gallery_images');