diff --git a/dev/test_router_support.py b/dev/test_router_support.py
index c7e8be2..8613174 100644
--- a/dev/test_router_support.py
+++ b/dev/test_router_support.py
@@ -156,6 +156,11 @@ class ImageEditMultipartTests(unittest.TestCase):
                 'Content-Disposition: form-data; name="prompt"\r\n\r\n'
                 "Nur die Farbe ändern\r\n"
             ).encode(),
+            (
+                f"--{boundary}\r\n"
+                'Content-Disposition: form-data; name="n"\r\n\r\n'
+                "1\r\n"
+            ).encode(),
             (
                 f"--{boundary}\r\n"
                 'Content-Disposition: form-data; name="image[]"; filename="a.png"\r\n'
@@ -174,6 +179,8 @@ class ImageEditMultipartTests(unittest.TestCase):
 
         self.assertEqual(fields["model"], "Qwen-Image-2.1-int8")
         self.assertEqual(fields["prompt"], "Nur die Farbe ändern")
+        normalized = handler._normalize_image_multipart_fields(fields)
+        self.assertEqual(normalized["n"], 1)
         self.assertEqual(
             files,
             [("image[]", "a.png", b"PNG-A"),
diff --git a/router/ai_profile_router.py b/router/ai_profile_router.py
index c3692d9..5e3285b 100755
--- a/router/ai_profile_router.py
+++ b/router/ai_profile_router.py
@@ -2229,6 +2229,7 @@ class Handler(BaseHTTPRequestHandler):
             try:
                 body = self._read_body()
                 files, data = self._parse_multipart_parts(body, content_type)
+                data = self._normalize_image_multipart_fields(data)
             except ValueError as exc:
                 self._send_error(400, str(exc),
                                  "invalid_request_error", "invalid_multipart")
@@ -2733,6 +2734,19 @@ class Handler(BaseHTTPRequestHandler):
 
         return files, fields
 
+    @staticmethod
+    def _normalize_image_multipart_fields(fields: dict[str, str]) -> dict:
+        """Konvertiert OpenAI-Formularzahlen in die JSON-API-Typen."""
+        normalized: dict = dict(fields)
+        for key in ("n", "steps"):
+            if key not in normalized:
+                continue
+            try:
+                normalized[key] = int(normalized[key])
+            except (TypeError, ValueError) as exc:
+                raise ValueError(f"'{key}' muss eine Ganzzahl sein") from exc
+        return normalized
+
     def _parse_multipart(self, data: bytes, content_type: str
                          ) -> tuple[bytes, str, dict]:
         """Kompatibler Einzeldatei-Wrapper für den STT-Pfad."""