class UploadHandler(blobstore_handlers.BlobstoreUploadHandler):

    def post(self):
        upload_files = self.get_uploads('file')
blob_info = upload_files[0]
imagedata = ImageData(parent=image_key(image_name))
imagedata.name = self.request.get('name')
imagedata.image = blob_info.key()
imagedata.put()
Google App Engine (Python) — Загрузка файла (изображения)