diff --git a/docs/examples.rst b/docs/examples.rst
index d4ad6dc..d50e7d2 100644
--- a/docs/examples.rst
+++ b/docs/examples.rst
@@ -28,8 +28,8 @@ Attach files or inline images:
 
 .. code-block:: python
 
-    message.attach(data=open('event.ics'), filename='Event.ics')
-    message.attach(data=open('image.png'), filename='image.png',
+    message.attach(data=open('event.ics', 'rb'), filename='Event.ics')
+    message.attach(data=open('image.png', 'rb'), filename='image.png',
                    content_disposition='inline')
 
 Use templates:
diff --git a/docs/index.rst b/docs/index.rst
index 21702d8..a256109 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -11,7 +11,7 @@ Modern email handling in python.
                        text=T("Build passed: {{ project_name }} ..."),
                        subject=T("Passed: {{ project_name }}#{{ build_id }}"),
                        mail_from=("CI", "ci@mycompany.com"))
-    m.attach(filename="icon.png", content_disposition="inline", data=open("icon.png"))
+    m.attach(filename="icon.png", content_disposition="inline", data=open("icon.png", "rb"))
     response = m.send(render={"project_name": "user/project1", "build_id": 121},
                       to='somebody@mycompany.com',
                       smtp={"host":"mx.mycompany.com", "port": 25})
diff --git a/docs/transformations.rst b/docs/transformations.rst
index 168b470..819d2bd 100644
--- a/docs/transformations.rst
+++ b/docs/transformations.rst
@@ -16,7 +16,7 @@ Code example to make images inline:
 .. code-block:: python
 
     >>> message = emails.Message(html="<img src='promo.png'>")
-    >>> message.attach(filename='promo.png', data=open('promo.png'))
+    >>> message.attach(filename='promo.png', data=open('promo.png', 'rb'))
     >>> message.attachments['promo.png'].is_inline = True
     >>> message.transformer.synchronize_inline_images()
     >>> message.transformer.save()
@@ -41,7 +41,7 @@ Load from zipfile or directory:
 
 .. code-block:: python
 
-    message = emails.loader.from_zipfile(open('design_pack.zip'))
+    message = emails.loader.from_zipfile(open('design_pack.zip', 'rb'))
     message = emails.loader.from_directory('/home/user/design_pack')
 
 Zipfile and directory loaders require at least one html file (with "html" extension).