diff --git a/litellm/llms/azure_ai/image_edit/mai_transformation.py b/litellm/llms/azure_ai/image_edit/mai_transformation.py
index da1da0c6e98..75bfc913a8f 100644
--- a/litellm/llms/azure_ai/image_edit/mai_transformation.py
+++ b/litellm/llms/azure_ai/image_edit/mai_transformation.py
@@ -1,4 +1,4 @@
-from typing import TYPE_CHECKING, Any, Dict, List, Optional, Tuple
+from typing import TYPE_CHECKING, Any, Dict, List, Optional, Tuple, cast
 
 import httpx
 from httpx._types import RequestFiles
@@ -43,8 +43,9 @@ class AzureFoundryMAIImageEditConfig(OpenAIImageEditConfig):
 
             if key in supported_params:
                 if key == "size" and value:
-                    self._validate_size_param(value)
-                    optional_params[key] = value
+                    size_param = cast(str, value)
+                    self._validate_size_param(size_param)
+                    optional_params[key] = size_param
                 else:
                     optional_params[key] = value
             elif not drop_params: