fix(images): forward image_config on OpenRouter image edits

litellm/images/main.py

@@ -836,13 +836,12 @@ def image_edit(
             raise ValueError(f"image edit is not supported for {custom_llm_provider}")
 
         local_vars.update(kwargs)
+        provider_supported_params: Final = frozenset(image_edit_provider_config.get_supported_openai_params(model))
         # Get ImageEditOptionalRequestParams with only valid parameters
         image_edit_optional_params: Final[ImageEditOptionalRequestParams] = (
             _get_ImageEditRequestUtils().get_requested_image_edit_optional_param(
                 local_vars,
-                provider_supported_params=frozenset(
-                    image_edit_provider_config.get_supported_openai_params(model)
-                ).intersection(non_default_params),
+                provider_supported_params=provider_supported_params.intersection(non_default_params),
             )
         )
         # Get optional parameters for the responses API
@@ -854,11 +853,14 @@ def image_edit(
             additional_drop_params=kwargs.get("additional_drop_params"),
         )
 
-        if image_edit_provider_config.use_multipart_form_data() and (
+        # Multipart OpenAI-compatible routes merge the caller's params here, flattened
+        # and with extra_body taking precedence; the default path below must not redo it.
+        merged_provider_params = image_edit_provider_config.use_multipart_form_data() and (
             custom_llm_provider == "openai"
             or custom_llm_provider == "azure"
             or custom_llm_provider in litellm.openai_compatible_providers
-        ):
+        )
+        if merged_provider_params:
             image_edit_request_params.update(
                 flatten_form_field_values(
                     non_default_params,
@@ -934,6 +936,18 @@ def image_edit(
                 client=kwargs.get("client"),
                 aimage_edit=_is_async,
             )
+        if not merged_provider_params:
+            # Forward caller-supplied params the provider config does not map itself
+            # (e.g. OpenRouter's image_config) on the default handler path; without this
+            # they are silently dropped before the request. Params the config supports were
+            # already mapped above (e.g. size -> width/height), so never re-add or override them.
+            image_edit_request_params.update(
+                {
+                    key: value
+                    for key, value in non_default_params.items()
+                    if key not in provider_supported_params and key not in image_edit_request_params
+                }
+            )
         # Call the handler with _is_async flag instead of directly calling the async handler
         return base_llm_http_handler.image_edit_handler(
             model=model,

litellm/llms/openrouter/image_edit/transformation.py

@@ -71,6 +71,13 @@
     LiteLLMLoggingObj = Any
 
 
+# OpenRouter routing/control fields that must not be forwarded from an image-edit
+# request body into the upstream /chat/completions call. Forwarding them would let
+# a caller of an allowed image-edit model redirect the request to other models or
+# providers, escaping LiteLLM's model-authorization and budget enforcement.
+OPENROUTER_ROUTING_CONTROL_PARAMS = frozenset({"models", "route", "provider", "transforms"})
+
+
 class OpenRouterImageEditConfig(BaseImageEditConfig):
     """
     Configuration for OpenRouter image editing via chat completions.
@@ -186,10 +193,17 @@ def transform_image_edit_request(
             "modalities": ["image", "text"],
         }
 
-        # Add mapped optional params (image_config, n, etc.)
+        # Add mapped optional params (image_config, n, etc.). Skip OpenRouter
+        # routing/control fields: these can arrive via forwarded non-default
+        # params, and copying them into the chat body would let a caller route
+        # an allowed image-edit request to other models/providers, bypassing
+        # LiteLLM's model-authorization and budget checks.
         for key, value in image_edit_optional_request_params.items():
-            if key not in ("model", "messages", "modalities"):
-                request_body[key] = value
+            if key in ("model", "messages", "modalities"):
+                continue
+            if key in OPENROUTER_ROUTING_CONTROL_PARAMS:
+                continue
+            request_body[key] = value
 
         empty_files: Final = cast(RequestFiles, [])
         return request_body, empty_files

tests/unit/images/test_image_edit_utils.py

@@ -269,6 +269,75 @@ def test_custom_pricing_not_detected_without_model_info(self):
         assert use_custom_pricing_for_model(litellm_params) is False
 
 
+class TestImageEditDefaultPathForwardsNonDefaultParams:
+    """
+    Regression test for https://github.com/BerriAI/litellm/issues/30753
+
+    image_config is honored on OpenRouter image generation but was silently dropped on
+    image edits: the default edit path never merged non_default_params (which still carries
+    image_config) before calling the handler, unlike the bedrock/stability/black_forest_labs
+    branches. The default handler path now merges them for every provider that reaches it
+    (openrouter, vertex_ai, ...) unless the multipart OpenAI-compatible branch already merged
+    them (flattened, with extra_body taking precedence), so they are forwarded instead of
+    dropped. OpenRouter's transform forwards extra top-level params, so once
+    image_config survives the merge it reaches the provider.
+    """
+
+    def _run_image_edit_and_capture(self, provider: str, model: str, image_config: dict):
+        from litellm.images.main import image_edit
+
+        with (
+            patch(
+                "litellm.images.main.get_llm_provider",
+                return_value=(model, provider, None, None),
+            ),
+            patch(
+                "litellm.images.main.ProviderConfigManager.get_provider_image_edit_config",
+                return_value=MagicMock(),
+            ),
+            patch(
+                "litellm.images.main._get_ImageEditRequestUtils",
+                return_value=MagicMock(
+                    get_requested_image_edit_optional_param=MagicMock(return_value={}),
+                    get_optional_params_image_edit=MagicMock(return_value={}),
+                ),
+            ),
+            patch("litellm.images.main.base_llm_http_handler") as mock_handler,
+        ):
+            mock_handler.image_edit_handler.return_value = MagicMock()
+
+            image_edit(
+                image=b"fake-image-data",
+                prompt="add a red border",
+                model=f"{provider}/{model}",
+                image_config=image_config,
+            )
+
+        return mock_handler.image_edit_handler.call_args.kwargs[
+            "image_edit_optional_request_params"
+        ]
+
+    def test_openrouter_image_edit_forwards_image_config(self):
+        image_config = {"aspect_ratio": "16:9", "image_size": "2K"}
+        forwarded = self._run_image_edit_and_capture(
+            provider="openrouter",
+            model="google/gemini-3-pro-image-preview",
+            image_config=image_config,
+        )
+        assert forwarded.get("image_config") == image_config
+
+    def test_default_path_forwards_image_config_for_non_openrouter_provider(self):
+        # The same silent-drop affected every non-multipart fallthrough provider, not just
+        # openrouter. (Multipart OpenAI-compatible providers merge them in their own branch.)
+        image_config = {"aspect_ratio": "1:1", "image_size": "1K"}
+        forwarded = self._run_image_edit_and_capture(
+            provider="vertex_ai",
+            model="imagen-3.0-capability-001",
+            image_config=image_config,
+        )
+        assert forwarded.get("image_config") == image_config
+
+
 class TestImageEditHandlerCredentialsForwarding:
     """
     Regression tests for Vertex AI image_edit credentials bug.

tests/unit/llms/openrouter/image_edit/test_openrouter_image_edit_transformation.py

@@ -237,6 +237,36 @@ def test_transform_image_edit_request_basic(self):
         # Files should be empty (JSON mode)
         assert list(files) == []
 
+    def test_transform_image_edit_request_drops_openrouter_routing_controls(self):
+        """Routing/control fields must not be forwarded into the chat body.
+
+        They can arrive via forwarded non-default params; copying OpenRouter
+        routing controls (models/route/provider/transforms) into the upstream
+        request would let a caller of an allowed image-edit model redirect the
+        call to other models/providers, bypassing LiteLLM's model-authorization
+        and budget checks. The intended image param (image_config) must still
+        pass through.
+        """
+        data, _ = self.config.transform_image_edit_request(
+            model=self.model,
+            prompt="Edit this",
+            image=self.sample_image_bytes,
+            image_edit_optional_request_params={
+                "image_config": {"aspect_ratio": "16:9"},
+                "models": ["openai/gpt-5", "anthropic/claude"],
+                "route": "fallback",
+                "provider": {"order": ["openai"]},
+                "transforms": ["middle-out"],
+            },
+            litellm_params=GenericLiteLLMParams(),
+            headers={},
+        )
+
+        for routing_key in ("models", "route", "provider", "transforms"):
+            assert routing_key not in data
+
+        assert data["image_config"] == {"aspect_ratio": "16:9"}
+
     def test_transform_image_edit_request_with_bytesio(self):
         """Test request transformation with BytesIO image input."""
         image = BytesIO(self.sample_image_bytes)