Merge pull request #2632 from wiredfool/issue_2628

Fix JPEG DPI when EXIF is invalid

PIL/JpegImagePlugin.py

@@ -119,8 +119,8 @@ def APP(self, marker):
 
     # If DPI isn't in JPEG header, fetch from EXIF
     if "dpi" not in self.info and "exif" in self.info:
-        exif = self._getexif()
         try:
+            exif = self._getexif()
             resolution_unit = exif[0x0128]
             x_resolution = exif[0x011A]
             try:
@@ -131,7 +131,9 @@ def APP(self, marker):
                 # 1 dpcm = 2.54 dpi
                 dpi *= 2.54
             self.info["dpi"] = dpi, dpi
-        except KeyError:
+        except (KeyError, SyntaxError):
+            # SyntaxError for invalid/unreadable exif
+            # KeyError for dpi not included
             self.info["dpi"] = 72, 72
 
 

Tests/test_file_jpeg.py

@@ -546,6 +546,15 @@ class TestFileJpeg(PillowTestCase):
         # http://www.exiv2.org/tags.html
         self.assertEqual(im.info.get("dpi"), (72, 72))
 
+    def test_invalid_exif(self):
+        # This is no-dpi-in-exif with the tiff header of the exif block
+        # hexedited from MM * to FF FF FF FF
+        im = Image.open("Tests/images/invalid-exif.jpg")
+
+        # This should return the default, and not a SyntaxError or
+        # OSError for unidentified image.
+        self.assertEqual(im.info.get("dpi"), (72, 72))
+
 
 @unittest.skipUnless(sys.platform.startswith('win32'), "Windows only")
 class TestFileCloseW32(PillowTestCase):