diff --git a/mcp_servers/image_gen_server.py b/mcp_servers/image_gen_server.py
index 697522e3d..327da5c03 100644
--- a/mcp_servers/image_gen_server.py
+++ b/mcp_servers/image_gen_server.py
@@ -33,7 +33,7 @@ async def list_tools() -> list[Tool]:
                     "prompt": {"type": "string", "description": "Image description prompt"},
                     "model": {"type": "string", "description": "Model name (auto-detects if omitted)"},
                     "size": {"type": "string", "description": "Image size (default 1024x1024)"},
-                    "quality": {"type": "string", "description": "Quality: low, medium, high, auto (default medium)"},
+                    "quality": {"type": "string", "description": "Quality: low, medium, high, auto (default configured quality, otherwise medium)"},
                 },
                 "required": ["prompt"],
             },
@@ -66,7 +66,7 @@ async def call_tool(name: str, arguments: dict) -> list[TextContent]:
 
         if not model_spec:
             model_spec = _settings.get("image_model", "")
-        if quality == "medium" and _settings.get("image_quality"):
+        if "quality" not in arguments and _settings.get("image_quality"):
             quality = _settings["image_quality"]
 
         # Auto-detect best available image model
diff --git a/src/ai_interaction.py b/src/ai_interaction.py
index dd772eff1..90294774a 100644
--- a/src/ai_interaction.py
+++ b/src/ai_interaction.py
@@ -1207,7 +1207,7 @@ async def do_generate_image(content: str, session_id: Optional[str] = None, owne
       Line 1: prompt describing the image
       Line 2: model name (optional, default auto-detects: prefers gpt-image-1.5 > gpt-image-1)
       Line 3: size (optional, defaults to 1024x1024)
-      Line 4: quality (optional, defaults to medium — options: low, medium, high, auto)
+      Line 4: quality (optional, defaults to configured quality or medium — low, medium, high, auto)
     """
     import base64
     import httpx
@@ -1225,13 +1225,13 @@ async def do_generate_image(content: str, session_id: Optional[str] = None, owne
         prompt = str(args.get('prompt') or '').strip()
         model_spec = str(args.get('model') or '').strip()
         size = str(args.get('size') or '1024x1024')
-        quality = str(args.get('quality') or 'medium')
+        quality = str(args.get('quality') or '')
     else:
         lines = content.strip().split("\n")
         prompt = lines[0].strip() if lines else ""
         model_spec = lines[1].strip() if len(lines) > 1 and lines[1].strip() else ""
         size = lines[2].strip() if len(lines) > 2 and lines[2].strip() else "1024x1024"
-        quality = lines[3].strip() if len(lines) > 3 and lines[3].strip() else "medium"
+        quality = lines[3].strip() if len(lines) > 3 and lines[3].strip() else ""
 
     if not prompt:
         return {"error": "Image prompt is required (line 1)"}
@@ -1249,8 +1249,8 @@ async def do_generate_image(content: str, session_id: Optional[str] = None, owne
     # Use admin-configured model/quality if not specified by the tool call
     if not model_spec:
         model_spec = _settings.get("image_model", "")
-    if quality == "medium" and _settings.get("image_quality"):
-        quality = _settings["image_quality"]
+    if not quality:
+        quality = _settings.get("image_quality") or "medium"
 
     # Auto-detect best available image model if still not set
     if not model_spec:
@@ -1482,7 +1482,7 @@ async def do_edit_image(
     session_id: Optional[str] = None,
     owner: Optional[str] = None,
     size: str = "auto",
-    quality: str = "medium",
+    quality: Optional[str] = None,
     progress_callback: Optional[Callable[[Dict[str, Any]], Awaitable[None]]] = None,
     incognito: bool = False,
 ) -> Dict:
@@ -1509,8 +1509,8 @@ async def do_edit_image(
 
     if not model_spec:
         model_spec = _settings.get("image_model", "")
-    if quality == "medium" and _settings.get("image_quality"):
-        quality = _settings["image_quality"]
+    if quality is None:
+        quality = _settings.get("image_quality") or "medium"
     if not model_spec:
         return {"error": "No image model selected for image editing"}
 
diff --git a/tests/test_image_quality_defaults.py b/tests/test_image_quality_defaults.py
new file mode 100644
index 000000000..090ab4166
--- /dev/null
+++ b/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