Added release notes

docs/reference/Image.rst

@@ -195,7 +195,6 @@ This helps to get the bounding box coordinates of the input image::
 .. automethod:: PIL.Image.Image.getpalette
 .. automethod:: PIL.Image.Image.getpixel
 .. automethod:: PIL.Image.Image.getprojection
-.. autoproperty:: PIL.Image.Image.has_transparency_data
 .. automethod:: PIL.Image.Image.histogram
 .. automethod:: PIL.Image.Image.paste
 .. automethod:: PIL.Image.Image.point
@@ -352,6 +351,8 @@ Instances of the :py:class:`Image` class have the following attributes:
 
     .. seealso:: :attr:`~Image.is_animated`, :func:`~Image.seek` and :func:`~Image.tell`
 
+.. autoattribute:: PIL.Image.Image.has_transparency_data
+
 Classes
 -------
 

docs/releasenotes/10.1.0.rst

@@ -32,10 +32,16 @@ TODO
 API Additions
 =============
 
-TODO
+has_transparency_data
-^^^^
+^^^^^^^^^^^^^^^^^^^^^
 
-TODO
+Images now have :py:attr:`~PIL.Image.Image.has_transparency_data` to indicate
+whether the image has transparency data, whether in the form of an alpha
+channel, a palette with an alpha channel, or a "transparency" key in the
+:py:attr:`~PIL.Image.Image.info` dictionary.
+
+Even if this attribute is true, the image might still appear solid, if all of
+the values shown within are opaque.
 
 Security
 ========