set icon using Uri c# CLASS from my application's folder

Feb 20 at 3:42 PM
While building the kml file to set an icon to placemark i need to use the Uri c# class, my problem is that i am unable to get the icon from my image folder inside my aplication project.
i tried the below one :
Uri uri = new Uri("pack://application:,,,/images/pignon.png");

but no luck. Is there any code example how to do that??