diff --git a/modules/api/models.py b/modules/api/models.py
index 6898f0a04..f44e5dca0 100644
--- a/modules/api/models.py
+++ b/modules/api/models.py
@@ -115,7 +115,7 @@ StableDiffusionImg2ImgProcessingAPI = PydanticModelGenerator(
     StableDiffusionProcessingImg2Img,
     [
         {"key": "sampler_index", "type": str, "default": "Euler"},
-        {"key": "init_images", "type": list, "default": []},
+        {"key": "init_images", "type": list | None, "default": None},
         {"key": "denoising_strength", "type": float, "default": 0.75},
         {"key": "mask", "type": str | None, "default": None},
         {"key": "include_init_images", "type": bool, "default": False, "exclude" : True},