Detach PyQt6 QPixmap instance before returning

.github/workflows/test-windows.yml

@@ -80,6 +80,12 @@ jobs:
         pytest-cov
         pytest-timeout
 
+    - name: Install CPython dependencies
+      if: "!contains(matrix.python-version, 'pypy')"
+      run: >
+        python3 -m pip install
+        PyQt6
+
     - name: Install dependencies
       id: install
       run: |

src/PIL/ImageQt.py

@@ -213,4 +213,7 @@ def toqimage(im: Image.Image | str | QByteArray) -> ImageQt:
 
 def toqpixmap(im: Image.Image | str | QByteArray) -> QPixmap:
     qimage = toqimage(im)
-    return getattr(QPixmap, "fromImage")(qimage)
+    pixmap = getattr(QPixmap, "fromImage")(qimage)
+    if qt_version == "6":
+        pixmap.detach()
+    return pixmap