Add an example script that turns all PNGs upside down.

examples/upsidedownternet.py

@@ -0,0 +1,9 @@
+import Image, cStringIO
+def response(context, flow):
+    if flow.response.headers["content-type"] == ["image/png"]:
+        s = cStringIO.StringIO(flow.response.content)
+        img = Image.open(s)
+        img = img.rotate(180)
+        s2 = cStringIO.StringIO()
+        img.save(s2, "png")
+        flow.response.content = s2.getvalue()