How to Hide the "Thumbnails like in Drupal" Admin Menu
function plt_hide_wp_drupal_imagecache_menus() {
//Hide the "Settings → Thumbnails like in Drupal" menu.
remove_submenu_page('options-general.php', 'wp-drupal-imagecache');
}
add_action('admin_menu', 'plt_hide_wp_drupal_imagecache_menus', 11);