code: def download(self, size=SIZE_XLARGE, thumbnail=False, wait=60, asynchronous=False):
          
          
          
          if thumbnail == True: size = SIZE_THUMBNAIL # backwards compatibility
          self._size = disambiguate_size(size)
          self._wait = wait
          self._asynchronous = asynchronous
  
          url  = "http://api.flickr.com/services/rest/?method=flickr.photos.getSizes"
          url += "&photo_id=" + self.id
          url += "&api_key=" + API_KEY
          URLAccumulator.__init__(self, url, wait, asynchronous, "flickr", ".xml", 2)
  
          if not asynchronous:
              return self.path
docs: Downloads this image to cache.
          
          Calling the download() method instantiates an asynchronous URLAccumulator
          that will fetch the image's URL from Flickr.
          A second process then downloads the file at the retrieved URL.
          
          Once it is done downloading, this image will have its path property
          set to an image file in the cache.