diff --git a/PIL/ImageFile.py b/PIL/ImageFile.py
index 0c7a19194..9ada2f6db 100644
--- a/PIL/ImageFile.py
+++ b/PIL/ImageFile.py
@@ -178,7 +178,7 @@ class ImageFile(Image.Image):
                     self.map = None
 
         self.load_prepare()
-        err_code = 0
+        err_code = -3 # initialize to unknown error
         if not self.map:
             # sort tiles in file order
             self.tile.sort(key=_tilesort)