I want to learn C# and I've put a simple button.. I want it to open an image when the user clicks the button. I don't know how to do that. Can you give me some advice please? I'm new here

Code:
namespace WpfApplication3
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, RoutedEventArgs e)
        {

        }
    }
}
Thanks in advance!