Image.StretchDirection Property

Image myImage1 = new Image();

// Set the stretch property.
myImage1.Stretch = Stretch.Fill;

// Set the StretchDirection property.
myImage1.StretchDirection = StretchDirection.Both;

// Create source
BitmapImage myBitmapImage1 = new BitmapImage();

// BitmapImage.UriSource must be in a BeginInit/EndInit block
myBitmapImage1.BeginInit();
myBitmapImage1.UriSource = new Uri(@"C:\Documents and Settings\All Users\Documents\My Pictures\Sample Pictures\Winter.jpg");
myBitmapImage1.EndInit();

//set image source
myImage1.Source = myBitmapImage1;