string userHeadPic = "http://123.56.178.100/headpic/7.jpg";

            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(userHeadPic);

            WebResponse response = request.GetResponse();

            System.Drawing.Image img = System.Drawing.Image.FromStream(response.GetResponseStream());

            Bitmap bitMap = new Bitmap(img);

            BitmapImage bitUserLogo = BitmapToBitmapImage(bitMap);

            SchoolPubData.UserInfo.imgHead.Source = bitUserLogo;

            SchoolPubData.MainForm.ToSchoolSwitchPage();

        public BitmapImage BitmapToBitmapImage(Bitmap bitmap)

        {

            Bitmap bitmapSource = new Bitmap(bitmap.Width, bitmap.Height);

            int i, j;

            for (i = 0; i < bitmap.Width; i++)

                for (j = 0; j < bitmap.Height; j++)

                {

                    System.Drawing.Color pixelColor = bitmap.GetPixel(i, j);

                    System.Drawing.Color newColor = System.Drawing.Color.FromArgb(pixelColor.R, pixelColor.G, pixelColor.B);

                    bitmapSource.SetPixel(i, j, newColor);

                }

            MemoryStream ms = new MemoryStream();

            bitmapSource.Save(ms, System.Drawing.Imaging.ImageFormat.Bmp);

            BitmapImage bitmapImage = new BitmapImage();

            bitmapImage.BeginInit();

            bitmapImage.StreamSource = new MemoryStream(ms.ToArray());

            bitmapImage.EndInit();

            return bitmapImage;

        }