Add release notes for #3608, #3861 and #3886 (#3930)

Add release notes for #3608, #3861 and #3886

CHANGES.rst

@@ -5,6 +5,12 @@ Changelog (Pillow)
 6.1.0 (unreleased)
 ------------------
 
+- Deprecate Image.__del__ #3929
+  [jdufresne]
+
+- Tiff: Add support for JPEG quality #3886
+  [olt]
+
 - Respect the PKG_CONFIG environment variable when building #3928
   [chewi]
 

docs/releasenotes/6.1.0.rst

@@ -30,6 +30,14 @@ Use instead:
 API Additions
 =============
 
+Image.entropy
+^^^^^^^^^^^^^
+Calculates and returns the entropy for the image. A bilevel image (mode "1") is treated
+as a greyscale ("L") image by this method.  If a mask is provided, the method employs
+the histogram for those parts of the image where the mask image is non-zero. The mask
+image must have the same size as the image, and be either a bi-level image (mode "1") or
+a greyscale image ("L").
+
 ImageGrab.grab
 ^^^^^^^^^^^^^^
 
@@ -66,8 +74,38 @@ ImageTk.getimage
 This function is now supported. It returns the contents of an ``ImageTk.PhotoImage`` as
 an RGBA ``Image.Image`` instance.
 
-Top To Bottom Complex Text Rendering
+Image quality for JPEG compressed TIFF
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+The TIFF encoder accepts a ``quality`` parameter for ``jpeg`` compressed TIFF files. A
+value from 0 (worst) to 100 (best) controls the image quality, similar to the JPEG
+encoder. The default is 75. For example:
+
+.. code-block:: python
+
+    im.save("out.tif", compression="jpeg", quality=85)
+
+Improve encoding of TIFF tags
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+The TIFF encoder supports more types, especially arrays. This is required for the
+GeoTIFF format which encodes geospatial information.
+
+* Pass ``tagtype`` from v2 directory to libtiff encoder, instead of autodetecting type.
+* Use explicit types eg. ``uint32_t`` for ``TIFF_LONG`` to fix issues on platforms with
+  64-bit longs.
+* Add support for multiple values (arrays). Requires type in v2 directory and values
+  must be passed as a tuple.
+* Add support for signed types eg. ``TIFFTypes.TIFF_SIGNED_SHORT``.
+
+Respect PKG_CONFIG environment variable when building
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+This variable is commonly used by other build systems and using it can help with
+cross-compiling. Falls back to ``pkg-config`` as before.
+
+Top-to-bottom complex text rendering
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-Drawing text in the 'ttb' direction with ImageFont has been significantly improved
+Drawing text in the 'ttb' direction with ``ImageFont`` has been significantly improved
 and requires Raqm 0.7 or greater.