diff --git a/README.md b/README.md
index 3c56233..541cb80 100644
--- a/README.md
+++ b/README.md
@@ -33,7 +33,11 @@ from pictures.models import PictureField
 
 class Profile(models.Model):
     title = models.CharField(max_length=255)
-    picture = PictureField(upload_to="avatars")
+    picture = PictureField(
+        upload_to="avatars", width_field="picture_width", height_field="picture_height"
+    )
+    picture_width = models.PositiveIntegerField(editable=False)
+    picture_height = models.PositiveIntegerField(editable=False)
 ```
 
 ```html
@@ -157,7 +161,11 @@ class Profile(models.Model):
     picture = PictureField(
         upload_to="avatars",
         aspect_ratios=[None, "1/1", "3/2", "16/9"],
+        width_field="picture_width",
+        height_field="picture_height",
     )
+    picture_width = models.PositiveIntegerField(editable=False)
+    picture_height = models.PositiveIntegerField(editable=False)
 ```
 
 ```html
@@ -235,10 +243,15 @@ class Profile(models.Model):
         validators=[
             MinSizeValidator(400, 300),  # At least 400x300 pixels
             MaxSizeValidator(4096, 4096),  # At most 4096x4096 pixels
-        ]
+        ],
+        width_field="picture_width",
+        height_field="picture_height",
     )
+    picture_width = models.PositiveIntegerField(editable=False)
+    picture_height = models.PositiveIntegerField(editable=False)
+
 
-Use `None` to limit only one dimension: `MaxSizeValidator(2048, None)` limits only width.
+# Use `None` to limit only one dimension: `MaxSizeValidator(2048, None)` limits only width.
 ```
 
 > [!IMPORTANT]
diff --git a/pictures/models.py b/pictures/models.py
index 4b3f326..77500d6 100644
--- a/pictures/models.py
+++ b/pictures/models.py
@@ -291,7 +291,7 @@ def _check_aspect_ratios(self):
         return errors
 
     def _check_width_height_field(self):
-        if None in self.aspect_ratios and not (self.width_field and self.height_field):
+        if not (self.width_field and self.height_field):
             return [
                 checks.Warning(
                     "width_field and height_field attributes are missing",
diff --git a/tests/test_models.py b/tests/test_models.py
index 00fa40c..b6af2ea 100644
--- a/tests/test_models.py
+++ b/tests/test_models.py
@@ -825,9 +825,19 @@ def test_check_aspect_ratios(self):
         assert errors
         assert errors[0].id == "fields.E100"
 
-    def test_check_width_height_field(self):
-        assert not PictureField(aspect_ratios=["3/2"])._check_width_height_field()
-        with override_field_aspect_ratios(Profile.picture.field, [None]):
+    @pytest.mark.parametrize(
+        "aspect_ratios",
+        [
+            ("3/2",),
+            (None,),
+            (
+                "3/2",
+                None,
+            ),
+        ],
+    )
+    def test_check_width_height_field(self, aspect_ratios):
+        with override_field_aspect_ratios(Profile.picture.field, aspect_ratios):
             errors = Profile.picture.field._check_width_height_field()
         assert errors
         assert errors[0].id == "fields.E101"