MemoryStream memStream = new MemoryStream();

            System.Windows.Media.Imaging.RenderTargetBitmap bmp = new System.Windows.Media.Imaging.RenderTargetBitmap((int)panel.ActualWidth, (int)panel.ActualHeight, 96d, 96d, System.Windows.Media.PixelFormats.Pbgra32);

            bmp.Render(panel);

            System.Windows.Media.Imaging.JpegBitmapEncoder encoder = new System.Windows.Media.Imaging.JpegBitmapEncoder();

            encoder.Frames.Add(System.Windows.Media.Imaging.BitmapFrame.Create(bmp));

            encoder.Save(memStream);

            byte[] bt = memStream.ToArray();

            memStream.Close();

            memStream = new MemoryStream(bt);

            BitmapImage biImg = new BitmapImage();

            biImg.BeginInit();

            biImg.StreamSource = memStream;

            biImg.EndInit();

            ImageBrush brush = new ImageBrush();

            brush.ImageSource = (ImageSource)biImg;

            imagePanel2.Background = brush;