diff --git a/src/PIL/BufrStubImagePlugin.py b/src/PIL/BufrStubImagePlugin.py
index 1cbd50d19..271db7258 100644
--- a/src/PIL/BufrStubImagePlugin.py
+++ b/src/PIL/BufrStubImagePlugin.py
@@ -37,7 +37,7 @@ class BufrStubImageFile(ImageFile.StubImageFile):
     format = "BUFR"
     format_description = "BUFR"
 
-    def _open(self):
+    def _open(self) -> None:
         offset = self.fp.tell()
 
         if not _accept(self.fp.read(4)):
diff --git a/src/PIL/CurImagePlugin.py b/src/PIL/CurImagePlugin.py
index b8790e209..85e2145e7 100644
--- a/src/PIL/CurImagePlugin.py
+++ b/src/PIL/CurImagePlugin.py
@@ -37,7 +37,7 @@ class CurImageFile(BmpImagePlugin.BmpImageFile):
     format = "CUR"
     format_description = "Windows Cursor"
 
-    def _open(self):
+    def _open(self) -> None:
         offset = self.fp.tell()
 
         # check magic
diff --git a/src/PIL/FpxImagePlugin.py b/src/PIL/FpxImagePlugin.py
index cfaf86239..4ba93bb39 100644
--- a/src/PIL/FpxImagePlugin.py
+++ b/src/PIL/FpxImagePlugin.py
@@ -237,7 +237,7 @@ class FpxImageFile(ImageFile.ImageFile):
 
         return ImageFile.ImageFile.load(self)
 
-    def close(self):
+    def close(self) -> None:
         self.ole.close()
         super().close()
 
diff --git a/src/PIL/FtexImagePlugin.py b/src/PIL/FtexImagePlugin.py
index a746959a3..7fcf81376 100644
--- a/src/PIL/FtexImagePlugin.py
+++ b/src/PIL/FtexImagePlugin.py
@@ -71,7 +71,7 @@ class FtexImageFile(ImageFile.ImageFile):
     format = "FTEX"
     format_description = "Texture File Format (IW2:EOC)"
 
-    def _open(self):
+    def _open(self) -> None:
         if not _accept(self.fp.read(4)):
             msg = "not an FTEX file"
             raise SyntaxError(msg)
diff --git a/src/PIL/GbrImagePlugin.py b/src/PIL/GbrImagePlugin.py
index 62197e36c..93e89b1e6 100644
--- a/src/PIL/GbrImagePlugin.py
+++ b/src/PIL/GbrImagePlugin.py
@@ -41,7 +41,7 @@ class GbrImageFile(ImageFile.ImageFile):
     format = "GBR"
     format_description = "GIMP brush file"
 
-    def _open(self):
+    def _open(self) -> None:
         header_size = i32(self.fp.read(4))
         if header_size < 20:
             msg = "not a GIMP brush"
diff --git a/src/PIL/GribStubImagePlugin.py b/src/PIL/GribStubImagePlugin.py
index a80fe0a23..13bdfa616 100644
--- a/src/PIL/GribStubImagePlugin.py
+++ b/src/PIL/GribStubImagePlugin.py
@@ -37,7 +37,7 @@ class GribStubImageFile(ImageFile.StubImageFile):
     format = "GRIB"
     format_description = "GRIB"
 
-    def _open(self):
+    def _open(self) -> None:
         offset = self.fp.tell()
 
         if not _accept(self.fp.read(8)):
diff --git a/src/PIL/ImImagePlugin.py b/src/PIL/ImImagePlugin.py
index 9c16159e9..a325f8552 100644
--- a/src/PIL/ImImagePlugin.py
+++ b/src/PIL/ImImagePlugin.py
@@ -119,7 +119,7 @@ class ImImageFile(ImageFile.ImageFile):
     format_description = "IFUNC Image Memory"
     _close_exclusive_fp_after_loading = False
 
-    def _open(self):
+    def _open(self) -> None:
         # Quick rejection: if there's not an LF among the first
         # 100 bytes, this is (probably) not a text header.
 
diff --git a/src/PIL/ImageTk.py b/src/PIL/ImageTk.py
index 10b2cc69a..2f9d7f505 100644
--- a/src/PIL/ImageTk.py
+++ b/src/PIL/ImageTk.py
@@ -128,7 +128,7 @@ class PhotoImage:
         if image:
             self.paste(image)
 
-    def __del__(self):
+    def __del__(self) -> None:
         name = self.__photo.name
         self.__photo.name = None
         try:
@@ -219,7 +219,7 @@ class BitmapImage:
             kw["data"] = image.tobitmap()
         self.__photo = tkinter.BitmapImage(**kw)
 
-    def __del__(self):
+    def __del__(self) -> None:
         name = self.__photo.name
         self.__photo.name = None
         try:
diff --git a/src/PIL/Jpeg2KImagePlugin.py b/src/PIL/Jpeg2KImagePlugin.py
index 697bad221..81ef32253 100644
--- a/src/PIL/Jpeg2KImagePlugin.py
+++ b/src/PIL/Jpeg2KImagePlugin.py
@@ -215,7 +215,7 @@ class Jpeg2KImageFile(ImageFile.ImageFile):
     format = "JPEG2000"
     format_description = "JPEG 2000 (ISO 15444)"
 
-    def _open(self):
+    def _open(self) -> None:
         sig = self.fp.read(4)
         if sig == b"\xff\x4f\xff\x51":
             self.codec = "j2k"
@@ -267,7 +267,7 @@ class Jpeg2KImageFile(ImageFile.ImageFile):
             )
         ]
 
-    def _parse_comment(self):
+    def _parse_comment(self) -> None:
         hdr = self.fp.read(2)
         length = _binary.i16be(hdr)
         self.fp.seek(length - 2, os.SEEK_CUR)
diff --git a/src/PIL/JpegImagePlugin.py b/src/PIL/JpegImagePlugin.py
index 715a358a3..7a3c99b6c 100644
--- a/src/PIL/JpegImagePlugin.py
+++ b/src/PIL/JpegImagePlugin.py
@@ -462,7 +462,7 @@ class JpegImageFile(ImageFile.ImageFile):
         box = (0, 0, original_size[0] / scale, original_size[1] / scale)
         return self.mode, box
 
-    def load_djpeg(self):
+    def load_djpeg(self) -> None:
         # ALTERNATIVE: handle JPEGs via the IJG command line utilities
 
         f, path = tempfile.mkstemp()
diff --git a/src/PIL/MpoImagePlugin.py b/src/PIL/MpoImagePlugin.py
index fb6620e75..eba35fb4d 100644
--- a/src/PIL/MpoImagePlugin.py
+++ b/src/PIL/MpoImagePlugin.py
@@ -100,7 +100,7 @@ class MpoImageFile(JpegImagePlugin.JpegImageFile):
     format_description = "MPO (CIPA DC-007)"
     _close_exclusive_fp_after_loading = False
 
-    def _open(self):
+    def _open(self) -> None:
         self.fp.seek(0)  # prep the fp in order to pass the JPEG test
         JpegImagePlugin.JpegImageFile._open(self)
         self._after_jpeg_open()
diff --git a/src/PIL/PSDraw.py b/src/PIL/PSDraw.py
index 848fc2f71..49c06ce13 100644
--- a/src/PIL/PSDraw.py
+++ b/src/PIL/PSDraw.py
@@ -54,7 +54,7 @@ class PSDraw:
         self.fp.write(b"%%EndProlog\n")
         self.isofont = {}
 
-    def end_document(self):
+    def end_document(self) -> None:
         """Ends printing. (Write PostScript DSC footer.)"""
         self.fp.write(b"%%EndDocument\nrestore showpage\n%%End\n")
         if hasattr(self.fp, "flush"):
diff --git a/src/PIL/PdfParser.py b/src/PIL/PdfParser.py
index c43f2da7b..077c9ec8b 100644
--- a/src/PIL/PdfParser.py
+++ b/src/PIL/PdfParser.py
@@ -409,28 +409,28 @@ class PdfParser:
         self.close()
         return False  # do not suppress exceptions
 
-    def start_writing(self):
+    def start_writing(self) -> None:
         self.close_buf()
         self.seek_end()
 
-    def close_buf(self):
+    def close_buf(self) -> None:
         try:
             self.buf.close()
         except AttributeError:
             pass
         self.buf = None
 
-    def close(self):
+    def close(self) -> None:
         if self.should_close_buf:
             self.close_buf()
         if self.f is not None and self.should_close_file:
             self.f.close()
             self.f = None
 
-    def seek_end(self):
+    def seek_end(self) -> None:
         self.f.seek(0, os.SEEK_END)
 
-    def write_header(self):
+    def write_header(self) -> None:
         self.f.write(b"%PDF-1.4\n")
 
     def write_comment(self, s):
@@ -450,7 +450,7 @@ class PdfParser:
         )
         return self.root_ref
 
-    def rewrite_pages(self):
+    def rewrite_pages(self) -> None:
         pages_tree_nodes_to_delete = []
         for i, page_ref in enumerate(self.orig_pages):
             page_info = self.cached_objects[page_ref]
@@ -529,7 +529,7 @@ class PdfParser:
         f.write(b"endobj\n")
         return ref
 
-    def del_root(self):
+    def del_root(self) -> None:
         if self.root_ref is None:
             return
         del self.xref_table[self.root_ref.object_id]
@@ -547,7 +547,7 @@ class PdfParser:
             except ValueError:  # cannot mmap an empty file
                 return b""
 
-    def read_pdf_info(self):
+    def read_pdf_info(self) -> None:
         self.file_size_total = len(self.buf)
         self.file_size_this = self.file_size_total - self.start_offset
         self.read_trailer()
diff --git a/src/PIL/PngImagePlugin.py b/src/PIL/PngImagePlugin.py
index 1547edde5..76e0abc31 100644
--- a/src/PIL/PngImagePlugin.py
+++ b/src/PIL/PngImagePlugin.py
@@ -179,7 +179,7 @@ class ChunkStream:
     def __exit__(self, *args):
         self.close()
 
-    def close(self):
+    def close(self) -> None:
         self.queue = self.fp = None
 
     def push(self, cid, pos, length):
@@ -370,14 +370,14 @@ class PngStream(ChunkStream):
             )
             raise ValueError(msg)
 
-    def save_rewind(self):
+    def save_rewind(self) -> None:
         self.rewind_state = {
             "info": self.im_info.copy(),
             "tile": self.im_tile,
             "seq_num": self._seq_num,
         }
 
-    def rewind(self):
+    def rewind(self) -> None:
         self.im_info = self.rewind_state["info"].copy()
         self.im_tile = self.rewind_state["tile"]
         self._seq_num = self.rewind_state["seq_num"]
diff --git a/src/PIL/PyAccess.py b/src/PIL/PyAccess.py
index 2c831913d..a9da90613 100644
--- a/src/PIL/PyAccess.py
+++ b/src/PIL/PyAccess.py
@@ -70,7 +70,7 @@ class PyAccess:
         # logger.debug("%s", vals)
         self._post_init()
 
-    def _post_init(self):
+    def _post_init(self) -> None:
         pass
 
     def __setitem__(self, xy, color):
diff --git a/src/PIL/QoiImagePlugin.py b/src/PIL/QoiImagePlugin.py
index 2875b8d75..cea8b60da 100644
--- a/src/PIL/QoiImagePlugin.py
+++ b/src/PIL/QoiImagePlugin.py
@@ -21,7 +21,7 @@ class QoiImageFile(ImageFile.ImageFile):
     format = "QOI"
     format_description = "Quite OK Image"
 
-    def _open(self):
+    def _open(self) -> None:
         if not _accept(self.fp.read(4)):
             msg = "not a QOI file"
             raise SyntaxError(msg)
diff --git a/src/PIL/WebPImagePlugin.py b/src/PIL/WebPImagePlugin.py
index 61ae9eae5..052f253cf 100644
--- a/src/PIL/WebPImagePlugin.py
+++ b/src/PIL/WebPImagePlugin.py
@@ -43,7 +43,7 @@ class WebPImageFile(ImageFile.ImageFile):
     __loaded = 0
     __logical_frame = 0
 
-    def _open(self):
+    def _open(self) -> None:
         if not _webp.HAVE_WEBPANIM:
             # Legacy mode
             data, width, height, self._mode, icc_profile, exif = _webp.WebPDecode(
diff --git a/src/PIL/WmfImagePlugin.py b/src/PIL/WmfImagePlugin.py
index 7f045ec7d..b0328657b 100644
--- a/src/PIL/WmfImagePlugin.py
+++ b/src/PIL/WmfImagePlugin.py
@@ -79,7 +79,7 @@ class WmfStubImageFile(ImageFile.StubImageFile):
     format = "WMF"
     format_description = "Windows Metafile"
 
-    def _open(self):
+    def _open(self) -> None:
         self._inch = None
 
         # check placable header
diff --git a/src/PIL/XpmImagePlugin.py b/src/PIL/XpmImagePlugin.py
index a638547af..88d14e9c2 100644
--- a/src/PIL/XpmImagePlugin.py
+++ b/src/PIL/XpmImagePlugin.py
@@ -36,7 +36,7 @@ class XpmImageFile(ImageFile.ImageFile):
     format = "XPM"
     format_description = "X11 Pixel Map"
 
-    def _open(self):
+    def _open(self) -> None:
         if not _accept(self.fp.read(9)):
             msg = "not an XPM file"
             raise SyntaxError(msg)