diff --git a/async-openai/src/types/chat.rs b/async-openai/src/types/chat.rs
index b60011d0..12dcde63 100644
--- a/async-openai/src/types/chat.rs
+++ b/async-openai/src/types/chat.rs
@@ -195,6 +195,7 @@ pub struct ImageUrl {
     /// Either a URL of the image or the base64 encoded image data.
     pub url: String,
     /// Specifies the detail level of the image. Learn more in the [Vision guide](https://platform.openai.com/docs/guides/vision/low-or-high-fidelity-image-understanding).
+    #[serde(skip_serializing_if = "Option::is_none")]
     pub detail: Option<ImageDetail>,
 }