Added reading of J2K comments

Tests/test_file_jpeg2k.py

@@ -424,8 +424,9 @@ def test_pclr() -> None:
 
 
 def test_comment() -> None:
-    with Image.open("Tests/images/comment.jp2") as im:
-        assert im.info["comment"] == b"Created by OpenJPEG version 2.5.0"
+    for path in ("Tests/images/9bit.j2k", "Tests/images/comment.jp2"):
+        with Image.open(path) as im:
+            assert im.info["comment"] == b"Created by OpenJPEG version 2.5.0"
 
     # Test an image that is truncated partway through a codestream
     with open("Tests/images/comment.jp2", "rb") as fp:

src/PIL/Jpeg2KImagePlugin.py

@@ -252,6 +252,7 @@ def _open(self) -> None:
         if sig == b"\xff\x4f\xff\x51":
             self.codec = "j2k"
             self._size, self._mode = _parse_codestream(self.fp)
+            self._parse_comment()
         else:
             sig = sig + self.fp.read(8)
 
@@ -262,6 +263,9 @@ def _open(self) -> None:
                 if dpi is not None:
                     self.info["dpi"] = dpi
                 if self.fp.read(12).endswith(b"jp2c\xff\x4f\xff\x51"):
+                    hdr = self.fp.read(2)
+                    length = _binary.i16be(hdr)
+                    self.fp.seek(length - 2, os.SEEK_CUR)
                     self._parse_comment()
             else:
                 msg = "not a JPEG 2000 file"
@@ -296,10 +300,6 @@ def _open(self) -> None:
         ]
 
     def _parse_comment(self) -> None:
-        hdr = self.fp.read(2)
-        length = _binary.i16be(hdr)
-        self.fp.seek(length - 2, os.SEEK_CUR)
-
         while True:
             marker = self.fp.read(2)
             if not marker: