Added "closed" attribute to images

Tests/test_image.py

@@ -928,6 +928,17 @@ class TestImage:
             im.apply_transparency()
             assert im.palette.colors[(27, 35, 6, 214)] == 24
 
+    def test_closed(self):
+        im = Image.open("Tests/images/hopper.jpg")
+        assert not im.closed
+
+        im.close()
+        assert im.closed
+
+        with Image.open("Tests/images/hopper.jpg") as im:
+            assert not im.closed
+        assert im.closed
+
     def test_categories_deprecation(self):
         with pytest.warns(DeprecationWarning):
             assert hopper().category == 0

docs/reference/open_files.rst

@@ -41,6 +41,7 @@ Image Lifecycle
 
 * ``Image.open()`` Filenames and ``Path`` objects are opened as a file.
   Metadata is read from the open file. The file is left open for further usage.
+  When an image is created, the ``closed`` property is set to ``False``.
 
 * ``Image.Image.load()`` When the pixel data from the image is
   required, ``load()`` is called. The current frame is read into
@@ -58,14 +59,16 @@ Image Lifecycle
   (e.g. multipage TIFF and animated GIF) the image file is left open so that
   ``Image.Image.seek()`` can load the appropriate frame.
 
-* ``Image.Image.close()`` Closes the file and destroys the core image object.
+* ``Image.Image.close()`` Closes the file, sets the ``closed`` property to
+  ``True`` and destroys the core image object.
 
-  The Pillow context manager will also close the file, but will not destroy
-  the core image object. e.g.::
+  The Pillow context manager will also close the file and update the ``closed``
+  property, but will not destroy the core image object. e.g.::
 
     with Image.open("test.jpg") as img:
         img.load()
     assert img.fp is None
+    assert img.closed
     img.save("test.png")
 
 

src/PIL/Image.py

@@ -519,6 +519,7 @@ class Image:
         self._category = 0
         self.readonly = 0
         self.pyaccess = None
+        self.closed = False
         self._exif = None
 
     def __getattr__(self, name):
@@ -567,6 +568,7 @@ class Image:
             if self.fp:
                 self.fp.close()
         self.fp = None
+        self.closed = True
 
     def close(self):
         """
@@ -594,6 +596,8 @@ class Image:
         if getattr(self, "map", None):
             self.map = None
 
+        self.closed = True
+
         # Instead of simply setting to None, we're setting up a
         # deferred error that will better explain that the core image
         # object is gone.