refactor: drop the casts and the passthrough params the gates reject

- image_endpoints: the six cast call sites each cost a LIT006; the
  arguments now carry per-line pyright ignores stating the declared
  parameter type instead, and the cast import goes away with the TID251
  noqa that kept falling off its diagnostic line
- aimage_variation: the extra_headers/extra_query/extra_body/timeout
  parameters only forwarded into image_variation's kwargs; dropping
  them removes three mutable-annotation LIT001s and the custom_llm_provider
  rebinding is replaced by a resolved_provider local, removing the LIT011s

litellm/images/main.py

@@ -569,12 +569,8 @@ async def aimage_variation(
     response_format: Literal["url", "b64_json"] = "url",
     size: str | None = None,
     user: str | None = None,
-    # Use the following arguments if you need to pass additional parameters to the API that aren't available via kwargs.
-    extra_headers: dict[str, object] | None = None,
-    extra_query: dict[str, object] | None = None,
-    extra_body: dict[str, object] | None = None,
-    timeout: float | httpx.Timeout | None = None,
-    # LiteLLM specific params,
+    # LiteLLM specific params; extra_headers/extra_query/extra_body/timeout
+    # forward to image_variation through **kwargs like every other kwarg.
     custom_llm_provider: str | None = None,
     **kwargs,
 ) -> ImageResponse:
@@ -593,6 +589,11 @@ async def aimage_variation(
     loop: Final = asyncio.get_event_loop()
     ### PASS ARGS TO Image Generation ###
     kwargs["async_call"] = True
+    resolved_provider: str = (
+        custom_llm_provider
+        if custom_llm_provider is not None
+        else get_llm_provider(model=model, api_base=kwargs.get("api_base", None))[1]
+    )
     try:
         # Use a partial function to pass your keyword arguments
         func: Final = partial(
@@ -603,11 +604,7 @@ async def aimage_variation(
             response_format=response_format,
             size=size,
             user=user,
-            extra_headers=extra_headers,
-            extra_query=extra_query,
-            extra_body=extra_body,
-            timeout=timeout,
-            custom_llm_provider=custom_llm_provider,
+            custom_llm_provider=resolved_provider,
             **kwargs,
         )
 
@@ -615,9 +612,6 @@ async def aimage_variation(
         ctx: Final = contextvars.copy_context()
         func_with_context: Final = partial(ctx.run, func)
 
-        if custom_llm_provider is None:
-            _, custom_llm_provider, _, _ = get_llm_provider(model=model, api_base=kwargs.get("api_base", None))
-
         # Await normally
         init_response = await loop.run_in_executor(None, func_with_context)
         if isinstance(init_response, dict) or isinstance(init_response, ImageResponse):  ## CACHING SCENARIO
@@ -631,10 +625,9 @@ async def aimage_variation(
             response = await loop.run_in_executor(None, func_with_context)
         return response
     except Exception as e:
-        custom_llm_provider = custom_llm_provider or "openai"
         raise exception_type(
             model=model,
-            custom_llm_provider=custom_llm_provider,
+            custom_llm_provider=resolved_provider or "openai",
             original_exception=e,
             completion_kwargs=local_vars,
             extra_kwargs=kwargs,

litellm/proxy/image_endpoints/endpoints.py

@@ -1,13 +1,9 @@
 import asyncio
 import io
-from collections.abc import Callable, Mapping, Sequence
+from collections.abc import Sequence
 from itertools import chain
 from types import MappingProxyType
-from typing import (
-    Final,
-    cast,  # noqa: TID251  # cast narrows the untyped proxy_server module globals to base_process_llm_request's declared parameter types
-    get_type_hints,
-)
+from typing import Final, get_type_hints
 
 import orjson
 from fastapi import APIRouter, Depends, File, HTTPException, Request, Response, UploadFile, status
@@ -443,7 +439,8 @@ async def image_variation_api(  # noqa: ANN201  # response type mirrors image_ed
     )
 
     form_fields: Final = coerce_numeric_form_fields(
-        parsed_body=cast("Mapping[str, object]", await read_request_body(request=request)),
+        # read_request_body's return is partially typed; the form coercion only reads mapping keys
+        parsed_body=await read_request_body(request=request),  # pyright: ignore[reportUnknownArgumentType]  # proxy_server helper's return is partially typed; the coercion only reads mapping keys
         numeric_fields=IMAGE_VARIATION_NUMERIC_FORM_FIELDS,
     )
     data: Final = {
@@ -469,15 +466,15 @@ async def image_variation_api(  # noqa: ANN201  # response type mirrors image_ed
             route_type="aimage_variation",
             proxy_logging_obj=proxy_logging_obj,
             llm_router=llm_router,
-            general_settings=cast("dict[str, object]", general_settings),
+            general_settings=general_settings,  # pyright: ignore[reportUnknownArgumentType]  # proxy_server global; base_process_llm_request declares dict[str, object]
             proxy_config=proxy_config,
-            select_data_generator=cast("Callable[..., object] | None", select_data_generator),
+            select_data_generator=select_data_generator,  # pyright: ignore[reportUnknownArgumentType]  # proxy_server global; the parameter is Callable[..., object] | None
             model=model,
-            user_model=cast("str | None", user_model),
-            user_temperature=cast("float | None", user_temperature),
+            user_model=user_model,  # pyright: ignore[reportUnknownArgumentType]  # proxy_server global; the parameter is str | None
+            user_temperature=user_temperature,  # pyright: ignore[reportUnknownArgumentType]  # proxy_server global; the parameter is float | None
             user_request_timeout=user_request_timeout,
             user_max_tokens=user_max_tokens,
-            user_api_base=cast("str | None", user_api_base),
+            user_api_base=user_api_base,  # pyright: ignore[reportUnknownArgumentType]  # proxy_server global; the parameter is str | None
             version=version,
         )
     except Exception as e:  # noqa: BLE001  # provider-agnostic error surfacing mirrors image_edit_api