function getCMSFields()
 {
     $photoManager = new PhotoAlbumPage_Manager($this, "Photos", "PhotoAlbumPage_Photo", "Photo", array("Caption" => "Caption"), "getCMSFields_forPopup");
     $photoManager->setUploadFolder(str_replace('assets/', '', $this->AssociatedFolder()->Filename));
     $fields = parent::GetCMSFields();
     $fields->addFieldToTab("Root.Content.Configuration", new NumericField('ThumbnailSize', 'Thumbnail size (pixels)'));
     $fields->addFieldToTab("Root.Content.Configuration", new NumericField('NormalSize', 'Normal size (pixels)'));
     $fields->addFieldToTab("Root.Content.Configuration", new NumericField('MediaPerPage', 'Number of images per page'));
     $fields->addFieldToTab('Root.Content.AlbumPhotos', $photoManager);
     $photos = DataObject::get("PhotoAlbumPage_Photo", "PhotoAlbumPageID = " . $this->ID);
     if ($photos && $photos->Count() > 0) {
         $coverPhotoField = new DropdownField('CoverImageID', 'Cover Photo', $photos->toDropdownMap('ID', 'Caption'));
         $coverPhotoField->setRightTitle('Choose a photo that will be used in holder pages.');
         $fields->addFieldToTab('Root.Content.Main', $coverPhotoField, 'Content');
     }
     return $fields;
 }