How to add additional class to an imagecache preset? Tried:

function ruh_imagecache_formatter_default($element) {
  // Inside a view $element may contain NULL data. In that case, just return.
  if (empty($element['#item']['fid'])) {
    return '';
  }

  // Extract the preset name from the formatter name.
  $presetname = substr($element['#formatter'], 0, strrpos($element['#formatter'], '_'));
  $style = 'linked';
  $style = 'default';

  $item = $element['#item'];
  $item['data']['alt'] = isset($item['data']['alt']) ? $item['data']['alt'] : '';
  $item['data']['title'] = isset($item['data']['title']) ? $item['data']['title'] : NULL;

  $class = "imagecache beautytips imagecache-$presetname imagecache-$style imagecache-{$element['#formatter']}";
  return theme('imagecache', $presetname, $item['filepath'], $item['data']['alt'], $item['data']['title'], array('class' =&gt; $class));
}

function ruh_imagecache_formatter_imagelink($element) {
  // Inside a view $element may contain NULL data. In that case, just return.
  if (empty($element['#item']['fid'])) {
    return '';
  }

  // Extract the preset name from the formatter name.
  $presetname = substr($element['#formatter'], 0, strrpos($element['#formatter'], '_'));
  $style = 'imagelink';

  $item = $element['#item'];
  $item['data']['alt'] = isset($item['data']['alt']) ? $item['data']['alt'] : '';
  $item['data']['title'] = isset($item['data']['title']) ? $item['data']['title'] : NULL;

  $imagetag = theme('imagecache', $presetname, $item['filepath'], $item['data']['alt'], $item['data']['title']);
  $path = file_create_url($item['filepath']);
  $class = "imagecache beautytips imagecache-$presetname imagecache-$style imagecache-{$element['#formatter']}";
  return l($imagetag, $path, array('attributes' =&gt; array('class' =&gt; $class), 'html' =&gt; TRUE));
}


I've added class - beautytips - but its not appearing on when im firebugging and imagecache image.
Add it as an array,

$class = array('imagecache', 'beautytips', 'class3');