10.2.0
------

Backwards Incompatible Changes
==============================

TODO
^^^^

TODO

Deprecations
============

ImageFile.raise_oserror
^^^^^^^^^^^^^^^^^^^^^^^

``ImageFile.raise_oserror()`` has been deprecated and will be removed in Pillow
12.0.0 (2025-10-15). The function is undocumented and is only useful for translating
error codes returned by a codec's ``decode()`` method, which ImageFile already does
automatically.

TODO
^^^^

TODO

API Changes
===========

Zero or negative font size error
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

When creating a :py:class:`~PIL.ImageFont.FreeTypeFont` instance, either directly or
through :py:func:`~PIL.ImageFont.truetype`, if the font size is zero or less, a
:py:exc:`ValueError` will now be raised.

API Additions
=============

Added DdsImagePlugin enums
^^^^^^^^^^^^^^^^^^^^^^^^^^

:py:class:`~PIL.DdsImagePlugin.DDSD`, :py:class:`~PIL.DdsImagePlugin.DDSCAPS`,
:py:class:`~PIL.DdsImagePlugin.DDSCAPS2`, :py:class:`~PIL.DdsImagePlugin.DDPF`,
:py:class:`~PIL.DdsImagePlugin.DXGI_FORMAT` and :py:class:`~PIL.DdsImagePlugin.D3DFMT`
enums have been added to :py:class:`PIL.DdsImagePlugin`.

JPEG restart marker interval
^^^^^^^^^^^^^^^^^^^^^^^^^^^^

When saving JPEG files, ``restart_marker_blocks`` and ``restart_marker_rows`` can now
be used to emit restart markers whenever the specified number of MCU blocks or rows
have been produced.

JPEG tables-only streamtype
^^^^^^^^^^^^^^^^^^^^^^^^^^^

When saving JPEG files, ``streamtype`` can now be set to 1, for tables-only. This will
output only the quantization and Huffman tables for the image.

Security
========

ImageFont.getmask: Applied ImageFont.MAX_STRING_LENGTH
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

To protect against potential DOS attacks when using arbitrary strings as text input,
Pillow will now raise a :py:exc:`ValueError` if the number of characters passed into
:py:meth:`PIL.ImageFont.ImageFont.getmask` is over a certain limit,
:py:data:`PIL.ImageFont.MAX_STRING_LENGTH`.

This threshold can be changed by setting :py:data:`PIL.ImageFont.MAX_STRING_LENGTH`. It
can be disabled by setting ``ImageFont.MAX_STRING_LENGTH = None``.

ImageMath.eval: Restricted environment keys
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

:cve:`2023-50447`: If an attacker has control over the keys passed to the
``environment`` argument of :py:meth:`PIL.ImageMath.eval`, they may be able to execute
arbitrary code. To prevent this, keys matching the names of builtins and keys
containing double underscores will now raise a :py:exc:`ValueError`.

Other Changes
=============

Added DDS BC4U and DX10 BC1 and BC4 reading
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Support has been added to read the BC4U format of DDS images.

Support has also been added to read DX10 BC1 and BC4, whether UNORM or
TYPELESS.

Optimized ImageStat.Stat count and extrema
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Calculating the :py:attr:`~PIL.ImageStat.Stat.count` and
:py:attr:`~PIL.ImageStat.Stat.extrema` statistics is now faster. After the
histogram is created in ``st = ImageStat.Stat(im)``, ``st.count`` is 3x as fast
on average and ``st.extrema`` is 12x as fast on average.

Encoder errors now report error detail as string
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

:py:exc:`OSError` exceptions from image encoders now include a textual description of
the error instead of a numeric error code.