diff --git a/helpers.py b/helpers.py
index 80ee9e33..0fdd366f 100644
--- a/helpers.py
+++ b/helpers.py
@@ -689,6 +689,13 @@ class DictAsObject(object):
 def fdiv(a, b):
     return np.true_divide(a,b)
 
+def add_extension_if_not_present(file_name, extension):
+    # This could conceivably be smarter about handling existing differing extensions
+    if(file_name[-len(extension):] != extension):
+        return file_name + extension
+    else:
+        return file_name
+
 # For debugging purposes
 
 def print_mobject_family(mob, n_tabs = 0):
diff --git a/scene/scene.py b/scene/scene.py
index 769ce11a..30e65fe3 100644
--- a/scene/scene.py
+++ b/scene/scene.py
@@ -511,7 +511,7 @@ class Scene(Container):
         if dont_update:
             folder = str(self)
         path = os.path.join(self.output_directory, folder)
-        file_name = (name or str(self)) + ".png"
+        file_name = add_extension_if_not_present(name or str(self), ".png")
         return os.path.join(path, file_name)
 
     def save_image(self, name = None, mode = "RGB", dont_update = False):