code: def getURL(self, size='Medium', urlType='url'):
          
          method = 'flickr.photos.getSizes'
          data = _doget(method, photo_id=self.id)
          for psize in data.rsp.sizes.size:
              if psize.label == size:
                  return getattr(psize, urlType)
          raise FlickrError, "No URL found"
docs: Retrieves a url for the photo.  (flickr.photos.getSizes)
  
          urlType - 'url' or 'source'
          'url' - flickr page of photo
          'source' - image file