Raise the same error if a truncated image is loaded a second time

Tests/test_file_jpeg.py

@@ -372,6 +372,10 @@ class TestFileJpeg(PillowTestCase):
         with self.assertRaises(IOError):
             im.load()
 
+        # Test that the error is raised if loaded a second time
+        with self.assertRaises(IOError):
+            im.load()
+
     def _n_qtables_helper(self, n, test_file):
         im = Image.open(test_file)
         f = self.tempfile("temp.jpg")

Tests/test_imagefile.py

@@ -113,6 +113,10 @@ class TestImageFile(PillowTestCase):
         with self.assertRaises(IOError):
             im.load()
 
+        # Test that the error is raised if loaded a second time
+        with self.assertRaises(IOError):
+            im.load()
+
     def test_truncated_without_errors(self):
         if "zip_encoder" not in codecs:
             self.skipTest("PNG (zlib) encoder not available")

src/PIL/ImageFile.py

@@ -243,7 +243,6 @@ class ImageFile(Image.Image):
                                 if LOAD_TRUNCATED_IMAGES:
                                     break
                                 else:
-                                    self.tile = []
                                     raise IOError(
                                         "image file is truncated "
                                         "(%d bytes not processed)" % len(b)

src/PIL/PngImagePlugin.py

@@ -612,7 +612,7 @@ class PngImageFile(ImageFile.ImageFile):
             rawmode, data = self.png.im_palette
             self.palette = ImagePalette.raw(rawmode, data)
 
-        self.__idat = length  # used by load_read()
+        self.__prepare_idat = length  # used by load_prepare()
 
     @property
     def text(self):
@@ -645,6 +645,7 @@ class PngImageFile(ImageFile.ImageFile):
         if self.info.get("interlace"):
             self.decoderconfig = self.decoderconfig + (1,)
 
+        self.__idat = self.__prepare_idat  # used by load_read()
         ImageFile.ImageFile.load_prepare(self)
 
     def load_read(self, read_bytes):