From 925277cbfcf881f04a5ace69f88a8b3f4ff5b992 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Lars=20J=C3=B8rgen=20Solberg?= <supersolberg@gmail.com>
Date: Mon, 7 Jul 2014 20:46:54 +0200
Subject: [PATCH] ensure that the prevous frame was loaded when seek()ing

---
 PIL/GifImagePlugin.py | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/PIL/GifImagePlugin.py b/PIL/GifImagePlugin.py
index cb96b9c95..4107c6ba3 100644
--- a/PIL/GifImagePlugin.py
+++ b/PIL/GifImagePlugin.py
@@ -101,6 +101,10 @@ class GifImageFile(ImageFile.ImageFile):
             self.__fp.seek(self.__rewind)
             self._prev_im = None
             self.disposal_method = 0
+        else:
+            # ensure that the previous frame was loaded
+            if not self.im:
+                self.load()
 
         if frame != self.__frame + 1:
             raise ValueError("cannot seek to frame %d" % frame)