diff --git a/comfy_api_nodes/nodes_quiver.py b/comfy_api_nodes/nodes_quiver.py
index 28862e368..3269c0afe 100644
--- a/comfy_api_nodes/nodes_quiver.py
+++ b/comfy_api_nodes/nodes_quiver.py
@@ -143,7 +143,7 @@ class QuiverTextToSVGNode(IO.ComfyNode):
         if reference_images:
             references = []
             for key in reference_images:
-                url = await upload_image_to_comfyapi(cls, reference_images[key])
+                url = await upload_image_to_comfyapi(cls, reference_images[key], mime_type="image/png")
                 references.append(QuiverImageObject(url=url))
             if len(references) > 4:
                 raise ValueError("Maximum 4 reference images are allowed.")
@@ -252,7 +252,7 @@ class QuiverImageToSVGNode(IO.ComfyNode):
         model: dict,
         seed: int,
     ) -> IO.NodeOutput:
-        image_url = await upload_image_to_comfyapi(cls, image)
+        image_url = await upload_image_to_comfyapi(cls, image, mime_type="image/png")
 
         response = await sync_op(
             cls,