$item['data'] is not unserialized

When image rendered by by views, data column value is not unserialized. I dirtily changed

function theme_imagecache_formatter($element) {
  if (isset($element['#item']['nid']) && $node = node_load($element['#item']['nid'])) {
    return imagecache_field_formatter($element['#field_name'], $element['#item'], $element['#formatter'], $node);
  }
}

to

function theme_imagecache_formatter($element) {
  if (isset($element['#item']['nid']) && $node = node_load($element['#item']['nid'])) {
    if (!is_array ($element['#item']['data'])) {
      $element['#item']['data'] = unserialize ($element['#item']['data']);
    }
    return imagecache_field_formatter($element['#field_name'], $element['#item'], $element['#formatter'], $node);
  }
}

Then it worked.