diff --git a/server-rs/crates/api-server/src/raw_image.rs b/server-rs/crates/api-server/src/raw_image.rs
index 9b4cde5ac..f26294861 100644
--- a/server-rs/crates/api-server/src/raw_image.rs
+++ b/server-rs/crates/api-server/src/raw_image.rs
@@ -185,7 +185,7 @@ fn decode_image(value: RawImageData, field: &str) -> Result<ReferenceImage, AppE
     }
     let bytes = BASE64_STANDARD
         .decode(value.data.trim())
-        .map_err(|error| bad_request(format!("{field}.data 必须是有效 base64：{error}")))?;
+        .map_err(|_| bad_request(format!("{field}.data 必须是有效 base64")))?;
     Ok(ReferenceImage {
         bytes,
         file_name: format!("{field}.png"),
@@ -254,4 +254,22 @@ mod tests {
             serde_json::json!({"data": [{"b64_json": "aGVsbG8="}]})
         );
     }
+
+    #[test]
+    fn invalid_base64_uses_generic_client_message() {
+        let payload = serde_json::json!({
+            "image": {"data": "not base64!", "mimeType": "image/png"},
+            "prompt": "edit",
+            "width": 1024,
+            "height": 1024
+        });
+        let parsed: RawImageEditRequest = serde_json::from_value(payload).expect("request");
+        let error = match prepare_request(parsed) {
+            Ok(_) => panic!("invalid base64 should fail"),
+            Err(error) => error,
+        };
+        let rendered = format!("{error:?}");
+        assert!(rendered.contains("image.data 必须是有效 base64"));
+        assert!(!rendered.contains("InvalidByte"));
+    }
 }