Welcomescreen: Smooth scaling of screen shots

Change-Id: Iab20d2d0dcfe378d4848c38d4a63041859249a0d
Reviewed-by: Thomas Hartmann <Thomas.Hartmann@digia.com>

src/plugins/qtsupport/screenshotcropper.cpp

@@ -96,7 +96,7 @@ QImage ScreenshotCropper::croppedImage(const QImage &sourceImage, const QString
             return result;
     }
 
-    return sourceImage.scaled(cropSize, Qt::KeepAspectRatio);
+    return sourceImage.scaled(cropSize, Qt::KeepAspectRatio, Qt::SmoothTransformation);
 }
 
 static int areaAttribute(const QXmlStreamAttributes &attributes, const QString &name)