diff --git a/docs/tutorials/asyncio-daemon.rst b/docs/tutorials/asyncio-daemon.rst
index 5f5bbc3d..ef651d6d 100644
--- a/docs/tutorials/asyncio-daemon.rst
+++ b/docs/tutorials/asyncio-daemon.rst
@@ -290,7 +290,7 @@ The dispatcher will control a list of the monitoring tasks. It will execute each
 to the configured schedule. The ``Monitor`` class is the base class for all the monitors. You can
 create different monitors by subclassing it and implementing the ``check()`` method.
 
-.. image:: asyncio-images/class_1.png
+.. image:: asyncio-images/classes-01.png
 
 Let's create dispatcher and the monitor base classes.
 
@@ -503,7 +503,7 @@ The ``HttpMonitor`` is a subclass of the ``Monitor``. We will implement the ``ch
 will send the HTTP request to the specified URL. The http request sending will be delegated to
 the ``HttpClient``.
 
-.. image:: asyncio-images/class_2.png
+.. image:: asyncio-images/classes-02.png
 
 First we need to create the ``HttpClient``.
 
diff --git a/docs/tutorials/asyncio-images/class_1.png b/docs/tutorials/asyncio-images/classes-01.png
similarity index 100%
rename from docs/tutorials/asyncio-images/class_1.png
rename to docs/tutorials/asyncio-images/classes-01.png
diff --git a/docs/tutorials/asyncio-images/class_2.png b/docs/tutorials/asyncio-images/classes-02.png
similarity index 100%
rename from docs/tutorials/asyncio-images/class_2.png
rename to docs/tutorials/asyncio-images/classes-02.png
diff --git a/docs/tutorials/cli-images/classes_01.png b/docs/tutorials/cli-images/classes-01.png
similarity index 100%
rename from docs/tutorials/cli-images/classes_01.png
rename to docs/tutorials/cli-images/classes-01.png
diff --git a/docs/tutorials/cli-images/classes_02.png b/docs/tutorials/cli-images/classes-02.png
similarity index 100%
rename from docs/tutorials/cli-images/classes_02.png
rename to docs/tutorials/cli-images/classes-02.png
diff --git a/docs/tutorials/cli.rst b/docs/tutorials/cli.rst
index 9e527432..26350cd1 100644
--- a/docs/tutorials/cli.rst
+++ b/docs/tutorials/cli.rst
@@ -50,7 +50,7 @@ inversion of control:
 
 Here is a class diagram of the Movie Lister application:
 
-.. image:: cli-images/classes_01.png
+.. image:: cli-images/classes-01.png
 
 The responsibilities are split next way:
 
@@ -285,7 +285,7 @@ We will add:
 
 After each step we will add the provider to the container.
 
-.. image:: cli-images/classes_02.png
+.. image:: cli-images/classes-02.png
 
 Create the ``entities.py`` in the ``movies`` package:
 
diff --git a/docs/tutorials/flask-images/screen_01.png b/docs/tutorials/flask-images/screen-01.png
similarity index 100%
rename from docs/tutorials/flask-images/screen_01.png
rename to docs/tutorials/flask-images/screen-01.png
diff --git a/docs/tutorials/flask-images/screen_02.png b/docs/tutorials/flask-images/screen-02.png
similarity index 100%
rename from docs/tutorials/flask-images/screen_02.png
rename to docs/tutorials/flask-images/screen-02.png
diff --git a/docs/tutorials/flask.rst b/docs/tutorials/flask.rst
index 115a066a..a4d42f84 100644
--- a/docs/tutorials/flask.rst
+++ b/docs/tutorials/flask.rst
@@ -43,7 +43,7 @@ How does Github Navigator work?
 - User can click on the repository, the repository owner or the last commit to open its web page
   on the Github.
 
-.. image::  flask-images/screen_02.png
+.. image::  flask-images/screen-02.png
 
 Prepare the environment
 -----------------------
@@ -416,7 +416,7 @@ Make sure the app is running or use ``flask run`` and open ``http://127.0.0.1:50
 
 You should see:
 
-.. image::  flask-images/screen_01.png
+.. image::  flask-images/screen-01.png
 
 Connect to the GitHub
 ---------------------
@@ -768,7 +768,7 @@ Make sure the app is running or use ``flask run`` and open ``http://127.0.0.1:50
 
 You should see:
 
-.. image::  flask-images/screen_02.png
+.. image::  flask-images/screen-02.png
 
 Make some refactoring
 ---------------------