Fix docs for chunk_size parameter

Closes #2122

Signed-off-by: Przemysław Adamek <[email protected]>

Author: adw1n

docker/models/images.py

@@ -64,9 +64,9 @@ def save(self, chunk_size=DEFAULT_DATA_CHUNK_SIZE):
         Get a tarball of an image. Similar to the ``docker save`` command.
 
         Args:
-            chunk_size (int): The number of bytes returned by each iteration
-                of the generator. If ``None``, data will be streamed as it is
-                received. Default: 2 MB
+            chunk_size (int): The generator will return up to that much data
+                per iteration, but may return less. If ``None``, data will be
+                streamed as it is received. Default: 2 MB
 
         Returns:
             (generator): A stream of raw archive data.