diff --git a/src/services/flow_current.py b/src/services/flow_current.py
index f3429902..9b411cb6 100644
--- a/src/services/flow_current.py
+++ b/src/services/flow_current.py
@@ -311,17 +311,15 @@ async def upload_image(
                     context,
                     base64.b64encode(image_bytes).decode("ascii"),
                     mime_type,
-                    True,
+                    1,
                     None,
                     None,
                     None,
-                    False,
-                    filename,
-                    self._map_frontend_image_aspect_ratio(aspect_ratio),
-                    None,
-                    None,
                     None,
+                    filename,
                     None,
+                    str(uuid.uuid4()).upper(),
+                    str(uuid.uuid4()).upper(),
                 ],
                 google_cookies=google_cookies,
                 token_id=token_id,
diff --git a/src/services/flow_frontend.py b/src/services/flow_frontend.py
index bf3345cf..0e9c41fc 100644
--- a/src/services/flow_frontend.py
+++ b/src/services/flow_frontend.py
@@ -189,29 +189,17 @@ def _build_frontend_image_generation_argument(
         reference_media_ids = [item for item in reference_media_ids if item]
         client_context = self._frontend_project_context(project_id, recaptcha_token)
         seed = random.randint(1, 2147483647)
-        generation_settings = json.dumps(
-            {
-                "imageModelKey": model_name,
-                "aspectRatio": self._map_frontend_image_aspect_ratio(aspect_ratio),
-                "seed": seed,
-                "count": 1,
-                "structuredPrompt": {"parts": [{"text": prompt}]},
-                "referenceImageMediaIds": reference_media_ids,
-            },
-            ensure_ascii=False,
-            separators=(",", ":"),
-        )
         request: List[Any] = [
             None,
             None,
-            [[1, item] for item in reference_media_ids] or None,
+            [[media_id, None, None, None, 1] for media_id in reference_media_ids] or None,
             seed,
             self._map_frontend_image_aspect_ratio(aspect_ratio),
             model_name,
             None,
             client_context,
             [[[prompt]]],
-            generation_settings if reference_media_ids else None,
+            None,
             None,
             None,
             None,
diff --git a/tests/test_flow_client_upload.py b/tests/test_flow_client_upload.py
index c2a03d93..de9f988e 100644
--- a/tests/test_flow_client_upload.py
+++ b/tests/test_flow_client_upload.py
@@ -40,6 +40,32 @@ async def test_upload_uses_current_frontend_rpc(self):
         self.assertEqual(request["argument"][0][10], ["captcha-token", 1])
         self.assertEqual(request["argument"][2], "image/jpeg")
 
+    async def test_upload_argument_matches_current_frontend_envelope(self):
+        client = FlowClient(proxy_manager=None)
+        client._get_recaptcha_token = AsyncMock(return_value=("captcha-token", None))
+        client._call_flow_frontend_rpc = AsyncMock(
+            return_value=[[MEDIA_ID, PROJECT_ID, f"https://flow-content.google/image/{MEDIA_ID}?Signature=1"]]
+        )
+        client._make_request = AsyncMock()
+
+        await client.upload_image(
+            at="frontend-cookie",
+            image_bytes=JPEG_BYTES,
+            aspect_ratio="IMAGE_ASPECT_RATIO_LANDSCAPE",
+            project_id=PROJECT_ID,
+            google_cookies="SID=session-cookie",
+        )
+
+        argument = client._call_flow_frontend_rpc.await_args.kwargs["argument"]
+        self.assertEqual(len(argument), 12)
+        # slot 3 is an integer enum; sending a bool makes the RPC reject with code=[3]
+        self.assertEqual(argument[3], 1)
+        self.assertIsInstance(argument[3], int)
+        self.assertIsNone(argument[7])
+        self.assertIsNone(argument[9])
+        for slot in (10, 11):
+            self.assertRegex(argument[slot], r"^[0-9A-F]{8}(-[0-9A-F]{4}){3}-[0-9A-F]{12}$")
+
     async def test_upload_requires_project_id(self):
         client = FlowClient(proxy_manager=None)
 
diff --git a/tests/test_flow_image_generation_args.py b/tests/test_flow_image_generation_args.py
new file mode 100644
index 00000000..93b7e40e
--- /dev/null
+++ b/tests/test_flow_image_generation_args.py
@@ -0,0 +1,48 @@
+import unittest
+
+from src.services.flow_client import FlowClient
+
+
+PROJECT_ID = "01234567-89ab-cdef-0123-456789abcdef"
+MEDIA_ID = "11234567-89ab-cdef-0123-456789abcdef"
+
+
+class FlowClientImageGenerationArgumentTests(unittest.TestCase):
+    def setUp(self):
+        self.client = FlowClient(proxy_manager=None)
+
+    def test_reference_images_use_media_envelope(self):
+        argument = self.client._build_frontend_image_generation_argument(
+            project_id=PROJECT_ID,
+            prompt="换成针织开衫",
+            model_name="NARWHAL",
+            aspect_ratio="IMAGE_ASPECT_RATIO_LANDSCAPE",
+            recaptcha_token="recaptcha-token",
+            session_id="session-id",
+            image_inputs=[{"name": MEDIA_ID}],
+        )
+
+        request = argument[1][0]
+        # the reference slot is a 5-field envelope, not [1, mediaId]
+        self.assertEqual(request[2], [[MEDIA_ID, None, None, None, 1]])
+        # slot 9 stays null; a serialized settings blob here is rejected
+        self.assertIsNone(request[9])
+        self.assertEqual(request[8], [[["换成针织开衫"]]])
+
+    def test_text_only_generation_omits_reference_slot(self):
+        argument = self.client._build_frontend_image_generation_argument(
+            project_id=PROJECT_ID,
+            prompt="一只红苹果",
+            model_name="NARWHAL",
+            aspect_ratio="IMAGE_ASPECT_RATIO_LANDSCAPE",
+            recaptcha_token="recaptcha-token",
+            session_id="session-id",
+        )
+
+        request = argument[1][0]
+        self.assertIsNone(request[2])
+        self.assertIsNone(request[9])
+
+
+if __name__ == "__main__":
+    unittest.main()