diff --git a/components/online_image.rst b/components/online_image.rst
index 7ac693fd5..a69fcb68d 100644
--- a/components/online_image.rst
+++ b/components/online_image.rst
@@ -37,6 +37,8 @@ Configuration variables
   - ``PNG``: The image on the server is encoded in PNG format.
 - **resize** (*Optional*, string): If set, this will resize the image to fit inside the given dimensions ``WIDTHxHEIGHT``
   and preserve the aspect ratio.
+- **placeholder** (**Optional**, :ref:`config-id`): ID of an :doc:`Image </components/image>` to display while the downloaded image is not yet ready.
+  This placeholder image will **not** be resized; regardless of the ``resize`` option value for the ``online_image``.
 - **type** (*Optional*): Specifies how to encode image internally. Defaults to ``BINARY``.
 
   - ``BINARY``: Two colors, suitable for 1 color displays or 2 color image in color displays. Uses 1 bit