Parse XMP tag bytes without decoding to string (#8960)

Co-authored-by: Andrew Murray <radarhere@users.noreply.github.com>

Author: radarhere

Tests/test_image.py

@@ -974,6 +974,11 @@ def test_exif_hide_offsets(self) -> None:
                     assert tag not in exif.get_ifd(0x8769)
                 assert exif.get_ifd(0xA005)
 
+    def test_exif_from_xmp_bytes(self) -> None:
+        im = Image.new("RGB", (1, 1))
+        im.info["xmp"] = b'\xff tiff:Orientation="2"'
+        assert im.getexif()[274] == 2
+
     def test_empty_xmp(self) -> None:
         with Image.open("Tests/images/hopper.gif") as im:
             if ElementTree is None:

src/PIL/Image.py

@@ -1542,10 +1542,11 @@ def getexif(self) -> Exif:
         # XMP tags
         if ExifTags.Base.Orientation not in self._exif:
             xmp_tags = self.info.get("XML:com.adobe.xmp")
+            pattern: str | bytes = r'tiff:Orientation(="|>)([0-9])'
             if not xmp_tags and (xmp_tags := self.info.get("xmp")):
-                xmp_tags = xmp_tags.decode("utf-8")
+                pattern = rb'tiff:Orientation(="|>)([0-9])'
             if xmp_tags:
-                match = re.search(r'tiff:Orientation(="|>)([0-9])', xmp_tags)
+                match = re.search(pattern, xmp_tags)
                 if match:
                     self._exif[ExifTags.Base.Orientation] = int(match[2])