diff --git a/wand/image.py b/wand/image.py
index 5fe132be..ad52f74a 100644
--- a/wand/image.py
+++ b/wand/image.py
@@ -4878,8 +4878,8 @@ def evaluate_images(self, operator=None):
            with Image() as img:
                 img.read(filename='first.png')
                 img.read(filename='second.png')
-                first.evaluate_images('add')
-                first.save(filename='sum.png')
+                with img.evaluate_images('add') as sum:
+                    sum.save(filename='sum.png')
 
         :param operator: Type of operation to calculate.
         :type operator: :const:`EVALUATE_OPS`