diff --git a/zds/tutorial/forms.py b/zds/tutorial/forms.py
index e2001098e8..29a7aab9c7 100644
--- a/zds/tutorial/forms.py
+++ b/zds/tutorial/forms.py
@@ -261,7 +261,7 @@ def __init__(self, *args, **kwargs):
 
         self.helper.layout = Layout(
             Field('title'),
-            Field('image'),
+            # Field('image'),  # disable because not used yet
             Field('introduction', css_class='md-editor'),
             Field('conclusion', css_class='md-editor'),
             Field('msg_commit'),
diff --git a/zds/tutorial/models.py b/zds/tutorial/models.py
index f8b2ea1213..b0d4a404ce 100644
--- a/zds/tutorial/models.py
+++ b/zds/tutorial/models.py
@@ -719,7 +719,8 @@ class Meta:
 
     image = models.ForeignKey(Image,
                               verbose_name='Image du chapitre',
-                              blank=True, null=True)
+                              blank=True, null=True,
+                              on_delete=models.SET_NULL)
     # This field is required in order to use pagination in chapters, see the
     # update_position_in_tutorial() method.
     position_in_tutorial = models.IntegerField('Position dans le tutoriel',