diff --git a/docs/advanced_topics/api/v2/configuration.rst b/docs/advanced_topics/api/v2/configuration.rst
index be54ab811..cfe390095 100644
--- a/docs/advanced_topics/api/v2/configuration.rst
+++ b/docs/advanced_topics/api/v2/configuration.rst
@@ -125,7 +125,7 @@ For example:
     class BlogPage(Page):
         published_date = models.DateTimeField()
         body = RichTextField()
-        feed_image = models.ForeignKey('wagtailimages.Image', on_delete=models.CASCADE, ...)
+        feed_image = models.ForeignKey('wagtailimages.Image', on_delete=models.SET_NULL, null=True, ...)
         private_field = models.CharField(max_length=255)
 
         # Export fields over the API
diff --git a/docs/advanced_topics/i18n/index.rst b/docs/advanced_topics/i18n/index.rst
index 1fd4ed191..2ccff03ed 100644
--- a/docs/advanced_topics/i18n/index.rst
+++ b/docs/advanced_topics/i18n/index.rst
@@ -143,7 +143,7 @@ For each field you would like to be translatable, duplicate it for every languag
         body_fr = StreamField(...)
 
         # Language-independent fields don't need to be duplicated
-        thumbnail_image = models.ForeignKey('wagtailimages.image', on_delete=models.CASCADE, ...)
+        thumbnail_image = models.ForeignKey('wagtailimages.Image', on_delete=models.SET_NULL, null=True, ...)
 
 .. note::