diff --git a/packages/python/plotly/_plotly_utils/utils.py b/packages/python/plotly/_plotly_utils/utils.py
index a2275374ea0..d0d43134a48 100644
--- a/packages/python/plotly/_plotly_utils/utils.py
+++ b/packages/python/plotly/_plotly_utils/utils.py
@@ -197,8 +197,8 @@ def encode_as_decimal(obj):
     @staticmethod
     def encode_as_pil(obj):
         """Attempt to convert PIL.Image.Image to base64 data uri"""
-        pil = get_module("PIL")
-        if isinstance(obj, pil.Image.Image):
+        image = get_module("PIL.Image")
+        if image is not None and isinstance(obj, image.Image):
             return ImageUriValidator.pil_image_to_uri(obj)
         else:
             raise NotEncodable
diff --git a/packages/python/plotly/plotly/tests/test_core/test_utils/test_utils.py b/packages/python/plotly/plotly/tests/test_core/test_utils/test_utils.py
index 7a8b5ca094e..27b77bd1d4c 100644
--- a/packages/python/plotly/plotly/tests/test_core/test_utils/test_utils.py
+++ b/packages/python/plotly/plotly/tests/test_core/test_utils/test_utils.py
@@ -15,6 +15,10 @@ def test_nan_to_null(self):
         expected_result = '[1, null, null, null, "platypus"]'
         self.assertEqual(result, expected_result)
 
+    def test_invalid_encode_exception(self):
+        with self.assertRaises(TypeError):
+            _json.dumps({"a": {1}}, cls=PlotlyJSONEncoder)
+
 
 class TestGetByPath(TestCase):
     def test_get_by_path(self):