ググってもやや引っかかりが悪かったのでメモ。
System.Windows.Controls.Image image = new System.Windows.Controls.Image();
image.Source = new System.Windows.Media.Imaging.BitmapImage(new System.Uri(@"C:\Documents and Settings\All Users\Documents\My Pictures\Sample Pictures\bike.jpg"));
image.ContextMenu = new System.Windows.Controls.ContextMenu();
System.Windows.Controls.MenuItem item = new System.Windows.Controls.MenuItem();
item.Header = "Click me!";
item.Click += new System.Windows.RoutedEventHandler(delegate(object obj, System.Windows.RoutedEventArgs args)
{
System.Windows.MessageBox.Show("hoge");
});
image.ContextMenu.Items.Add(item);
