$id = $this->getRequest()->get('id');
Validate the id, make sure it's just an integer, validate the user's right to edit that
object, then...
$this->get('punkave.file_upload').handleFileUpload(array('folder' => 'photos/' . $id))
DOES NOT RETURN. The response is generated in native PHP by BlueImp's UploadHandler class.
Note that if %file_uploader.file_path%/$folder already contains files, the user is
permitted to delete those in addition to uploading more. This is why we use a
separate folder for each object's associated files.
Any passed options are merged with the service parameters. You must specify
the 'folder' option to distinguish this set of uploaded files
from others.