<?php
class CaseStudy extends Page {

   static $has_many = array ('CaseStudyImages' => 'CaseStudy_Image');

   public function getCMSFields() {
      $fields = parent::getCMSFields();
      $fields->addFieldToTab("Root.Content.Object",$manager = new DataObjectManager($this,'CaseStudyImages','CaseStudy_Image',array('Name' => 'Name','CMSThumbnail'=>'Preview'),'getCMSFields_forPopup',null,"Name Asc"));
   return $fields;
   }
}
class CaseStudy_Image extends DataObject
{
static $db = array (
'Name' => 'Varchar'
);

static $has_one = array (
'Attachment' => 'Image',
'Thumbnail' => 'Image',
'CaseStudy' => 'CaseStudy'
);

public function getCMSFields_forPopup()
{
return new FieldSet(
   new ImageField('Thumbnail'),
   new TextField('Name'),
   new ImageField('Attachment')
);
}
   function CMSThumbnail() {
      if ($image=$this->Thumbnail())return $image->CMSThumbnail();
      return null;
   }
}