Added DeferredError to _fp

Tests/test_file_apng.py

@@ -637,6 +637,15 @@ def test_apng_save_blend(tmp_path):
         assert im.getpixel((0, 0)) == (0, 255, 0, 255)
 
 
+def test_seek_after_close():
+    im = Image.open("Tests/images/apng/delay.png")
+    im.seek(1)
+    im.close()
+
+    with pytest.raises(ValueError):
+        im.seek(0)
+
+
 def test_constants_deprecation():
     for enum, prefix in {
         PngImagePlugin.Disposal: "APNG_DISPOSE_",

Tests/test_file_fli.py

@@ -46,6 +46,15 @@ def test_closed_file():
         im.close()
 
 
+def test_seek_after_close():
+    im = Image.open(animated_test_file)
+    im.seek(1)
+    im.close()
+
+    with pytest.raises(ValueError):
+        im.seek(0)
+
+
 def test_context_manager():
     with warnings.catch_warnings():
         with Image.open(static_test_file) as im:

Tests/test_file_gif.py

@@ -46,6 +46,19 @@ def test_closed_file():
         im.close()
 
 
+def test_seek_after_close():
+    im = Image.open("Tests/images/iss634.gif")
+    im.load()
+    im.close()
+
+    with pytest.raises(ValueError):
+        im.is_animated
+    with pytest.raises(ValueError):
+        im.n_frames
+    with pytest.raises(ValueError):
+        im.seek(1)
+
+
 def test_context_manager():
     with warnings.catch_warnings():
         with Image.open(TEST_GIF) as im:

Tests/test_file_mpo.py

@@ -48,6 +48,14 @@ def test_closed_file():
         im.close()
 
 
+def test_seek_after_close():
+    im = Image.open(test_files[0])
+    im.close()
+
+    with pytest.raises(ValueError):
+        im.seek(1)
+
+
 def test_context_manager():
     with warnings.catch_warnings():
         with Image.open(test_files[0]) as im:

Tests/test_file_tiff.py

@@ -70,6 +70,15 @@ class TestFileTiff:
             im.load()
             im.close()
 
+    def test_seek_after_close(self):
+        im = Image.open("Tests/images/multipage.tiff")
+        im.close()
+
+        with pytest.raises(ValueError):
+            im.n_frames
+        with pytest.raises(ValueError):
+            im.seek(1)
+
     def test_context_manager(self):
         with warnings.catch_warnings():
             with Image.open("Tests/images/multipage.tiff") as im:

src/PIL/Image.py

@@ -547,7 +547,7 @@ class Image:
             if getattr(self, "_fp", False):
                 if self._fp != self.fp:
                     self._fp.close()
-                self._fp = None
+                self._fp = DeferredError(ValueError("Operation on closed image"))
             if self.fp:
                 self.fp.close()
         self.fp = None
@@ -568,7 +568,7 @@ class Image:
             if getattr(self, "_fp", False):
                 if self._fp != self.fp:
                     self._fp.close()
-                self._fp = None
+                self._fp = DeferredError(ValueError("Operation on closed image"))
             if self.fp:
                 self.fp.close()
             self.fp = None