Load EXIF from PNG where eXIf chunk is after first IDAT chunk

Tests/test_file_png.py

@@ -591,6 +591,21 @@ class TestFilePng(PillowTestCase):
         self.assertEqual(im.text, {'TXT': 'VALUE', 'ZIP': 'VALUE'})
 
     def test_exif(self):
+        im = Image.open("Tests/images/exif.png")
+        exif = im._getexif()
+        self.assertEqual(exif[274], 1)
+
+    def test_exif_save(self):
+        im = Image.open("Tests/images/exif.png")
+
+        test_file = self.tempfile("temp.png")
+        im.save(test_file)
+
+        reloaded = Image.open(test_file)
+        exif = reloaded._getexif()
+        self.assertEqual(exif[274], 1)
+
+    def test_exif_from_jpg(self):
         im = Image.open("Tests/images/pil_sample_rgb.jpg")
 
         test_file = self.tempfile("temp.png")

docs/handbook/image-file-formats.rst

@@ -462,6 +462,10 @@ PNG
 Pillow identifies, reads, and writes PNG files containing ``1``, ``L``, ``P``,
 ``RGB``, or ``RGBA`` data. Interlaced files are supported as of v1.1.7.
 
+As of Pillow 6.0, EXIF data can be read from PNG images. However, unlike other
+image formats, EXIF data is not guaranteed to have been read until
+:py:meth:`~PIL.Image.Image.load` has been called.
+
 The :py:meth:`~PIL.Image.Image.open` method sets the following
 :py:attr:`~PIL.Image.Image.info` properties, when appropriate:
 
@@ -527,6 +531,11 @@ The :py:meth:`~PIL.Image.Image.save` method supports the following options:
 **icc_profile**
     The ICC Profile to include in the saved file.
 
+**exif**
+    The exif data to include in the saved file.
+
+    .. versionadded:: 6.0.0
+
 **bits (experimental)**
     For ``P`` images, this option controls how many bits to store. If omitted,
     the PNG writer uses 8 bits (256 colors).

docs/releasenotes/6.0.0.rst

@@ -112,6 +112,13 @@ Image.quantize
 
 The `dither` option is now a customisable parameter (was previously hardcoded to `1`). This parameter takes the same values used in `Image.convert`
 
+PNG EXIF Data
+^^^^^^^^^^^^^
+
+EXIF data can now be read from and saved to PNG images. However, unlike other image
+formats, EXIF data is not guaranteed to have been read until
+:py:meth:`~PIL.Image.Image.load` has been called.
+
 Other Changes
 =============
 

src/PIL/PngImagePlugin.py

@@ -689,6 +689,8 @@ class PngImageFile(ImageFile.ImageFile):
         self.png = None
 
     def _getexif(self):
+        if "exif" not in self.info:
+            self.load()
         from .JpegImagePlugin import _getexif
         return _getexif(self)