Ticket #8817: 8817.diff

django/core/files/images.py

@@ -28 +28 @@
     """Returns the (width, height) of an image, given an open file or a path."""
     from PIL import ImageFile as PILImageFile
     p = PILImageFile.Parser()
-    if hasattr(file_or_path, 'read'):
+    needs_close = True
+    # If we have a file name, prefer to open a new file to avoid modifying the
+    # state of the file object we were given.
+    if hasattr(file_or_path, 'name'):
+        # If this is a FileField, use custom storage backend to re-open file
+        if hasattr(file_or_path, 'storage'):
+            file = file_or_path.storage.open(file_or_path.name, 'rb')
+        else:
+            file = open(file_or_path.name, 'rb')
+    elif hasattr(file_or_path, 'read'):
         file = file_or_path
+        needs_close = False
     else:
         file = open(file_or_path, 'rb')
     while 1:
@@ -38 +48 @@
             break
         p.feed(data)
         if p.image:
+            if needs_close:
+                file.close()
             return p.image.size
+    if needs_close:
+        file.close()
     return None