diff -r e7822b0be417 -r 58c9e2de0dd4 pngtile/tile.py
--- a/pngtile/tile.py	Sat Oct 04 02:46:44 2014 +0300
+++ b/pngtile/tile.py	Sat Oct 04 03:03:17 2014 +0300
@@ -170,13 +170,14 @@
             ttime = None
 
         if request.if_modified_since and mtime == request.if_modified_since:
-            return Response(status=304)
-            
-        # render
-        png = render_func(request, image)
+            response = Response(status=304)
+        else:
+            # render 
+            png = render_func(request, image)
         
-        # response
-        response = Response(png, content_type='image/png')
+            response = Response(png, content_type='image/png')
+        
+        # cache out
         response.last_modified = mtime
 
         if not ttime: