GIFs change mode for later frames [ci skip]

python-pillow · Nov 29, 2021 · eeb685b · eeb685b
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commit eeb685b
Showing 1 changed file with 3 additions and 2 deletions.
diff --git a/docs/handbook/image-file-formats.rst b/docs/handbook/image-file-formats.rst
@@ -91,8 +91,9 @@ Pillow reads GIF87a and GIF89a versions of the GIF file format. The library
 writes run-length encoded files in GIF87a by default, unless GIF89a features
 are used or GIF89a is already in use.
 
-Note that GIF files are always read as grayscale (``L``)
-or palette mode (``P``) images.
+GIF files are initially read as grayscale (``L``) or palette mode (``P``)
+images, but seeking to later frames in an image will change the mode to either
+``RGB`` or ``RGBA``, depending on whether the first frame had transparency.
 
 The :py:meth:`~PIL.Image.open` method sets the following
 :py:attr:`~PIL.Image.Image.info` properties: