<?php
/**
* Defines the Fotos
*/
class Fotos extends DataObject {
static $db = array(
'SmallCapt' => 'Text',
'LargeCapt' => 'Text'
);

static $has_one = array(
'SmallFoto' => 'Image',
'LargeFoto' => 'Image',
'MySiteTree' => 'SiteTree'
);

function getCMSFields_forPopup() {
$fields = new FieldSet();

$fields->push( new SimpleImageField( 'SmallFoto', 'Kleine foto') );
$fields->push( new Textfield( 'SmallCapt', 'Beschr. kleine foto' ) );
$fields->push( new SimpleImageField( 'LargeFoto', 'Grote foto' ) );
$fields->push( new Textfield( 'LargeCapt', 'Beschtr. grote foto' ) );

return $fields;
}
}
?>

...
public static $has_many = array(
'MyFotos' => 'Fotos'
   );

function getCMSFields() {
$fields = parent::getCMSFields();
$tablefield = new HasManyComplexTableField(
$this,
'MyFotos',
'Fotos',
array(
'SmallFoto' => 'Kleine foto',
'SmallCapt' => 'Beschrijving',
'LargeFoto' => 'Grote foto',
'LargeCapt' => 'Beschrijving'
),
'getCMSFields_forPopup'
);

$fields->addFieldToTab('Root.Content.Fotos', $tablefield );
return $fields;
}
...