Reply to self, this work:
$sizes = array('main' => array('width' => $this->baseObject->config->get('config_image_popup_width'),
'height' => $this->baseObject->config->get('config_image_popup_height')),
'thumb' => array('width' => $this->baseObject->config->get('config_image_thumb_width'),
'height' => $this->baseObject->config->get('config_image_thumb_height')));
$main_image = $resource->getResourceAllObjects('products', $product_id, $sizes, 1, false);