diff --git a/api/onnx_web/chain/reduce_thumbnail.py b/api/onnx_web/chain/reduce_thumbnail.py
index 50cccc1d..9114c289 100644
--- a/api/onnx_web/chain/reduce_thumbnail.py
+++ b/api/onnx_web/chain/reduce_thumbnail.py
@@ -20,6 +20,9 @@ def reduce_thumbnail(
     **kwargs,
 ) -> Image.Image:
     image = source_image.copy()
+
+    # TODO: should use a call to valid_image
     image = image.thumbnail((size.width, size.height))
+
     logger.info("created thumbnail with dimensions: %sx%s", image.width, image.height)
     return image
diff --git a/api/onnx_web/params.py b/api/onnx_web/params.py
index 1a645056..4a744138 100644
--- a/api/onnx_web/params.py
+++ b/api/onnx_web/params.py
@@ -54,6 +54,9 @@ class Size:
         self.width = width
         self.height = height
 
+    def __iter__(self):
+        return iter([self.width, self.height])
+
     def __str__(self) -> str:
         return "%sx%s" % (self.width, self.height)