fix(images): preserve explicit medium quality requests

Use configured quality only for omitted arguments in generation, MCP and edit helpers. Keep explicit medium choices from being overwritten by a low or high default.

tests/test_image_quality_defaults.py

@@ -0,0 +1,74 @@
+"""Explicit quality choices must take precedence over the configured default."""
+import asyncio
+import json
+
+import pytest
+from PIL import Image
+
+
+@pytest.mark.parametrize("caller", ["json", "lines", "mcp", "edit"])
+@pytest.mark.parametrize("requested,configured,expected", [
+    ("medium", "high", "medium"),
+    ("medium", "low", "medium"),
+    ("low", "high", "low"),
+    ("high", "low", "high"),
+    ("auto", "high", "auto"),
+    (None, "high", "high"),
+    (None, None, "medium"),
+])
+def test_image_quality_precedence(monkeypatch, tmp_path, caller, requested, configured, expected):
+    from src import ai_interaction, settings
+    from mcp_servers.image_gen_server import call_tool
+
+    config = {"image_gen_enabled": True, "image_model": "gpt-image-1"}
+    if configured is not None:
+        config["image_quality"] = configured
+    monkeypatch.setattr(settings, "load_settings", lambda: config)
+    monkeypatch.setattr(ai_interaction, "_resolve_model", lambda *args, **kwargs:
+                        ("http://fixture.invalid/v1/chat/completions", "gpt-image-1", {}))
+    captured = []
+
+    class Response:
+        status_code = 418
+        text = "Fixture captured request"
+
+        def json(self):
+            return {"error": {"message": self.text}}
+
+    class Client:
+        def __init__(self, *args, **kwargs):
+            pass
+
+        async def __aenter__(self):
+            return self
+
+        async def __aexit__(self, *args):
+            pass
+
+        async def post(self, url, **kwargs):
+            captured.append(kwargs.get("json") or kwargs.get("data"))
+            return Response()
+
+    monkeypatch.setattr("httpx.AsyncClient", Client)
+    args = {"prompt": "Fixture image", "model": "gpt-image-1"}
+    if requested is not None:
+        args["quality"] = requested
+    if caller == "json":
+        operation = ai_interaction.do_generate_image(json.dumps(args), incognito=True)
+    elif caller == "lines":
+        content = "Fixture image\ngpt-image-1\n1024x1024"
+        if requested is not None:
+            content += "\n" + requested
+        operation = ai_interaction.do_generate_image(content, incognito=True)
+    elif caller == "mcp":
+        operation = call_tool("generate_image", args)
+    else:
+        source = tmp_path / "fixture.png"
+        Image.new("RGB", (2, 2), "white").save(source)
+        kwargs = {} if requested is None else {"quality": requested}
+        operation = ai_interaction.do_edit_image("Fixture image", str(source), size="1024x1024",
+                                               incognito=True, **kwargs)
+    result = asyncio.run(operation)
+    assert "418" in str(result), result
+    assert len(captured) == 1
+    assert captured[0]["quality"] == expected