### ImgToBase64

 private String ImgToBase64String(string Imagefilename)
        {
            String strbaser64 = null;
            try
            {
                Bitmap bmp = new Bitmap(Imagefilename);
                
                 

                MemoryStream ms = new MemoryStream();
                bmp.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
                byte[] arr = new byte[ms.Length];
                ms.Position = 0;
                ms.Read(arr, 0, (int)ms.Length);
                ms.Close();
                strbaser64 = Convert.ToBase64String(arr);
                // MessageBox.Show("转换成功!");
            }
            catch (Exception ex)
            {
                MessageBox.Show("ImgToBase64String 转换失败\nException:" + ex.Message);
            }
            return strbaser64;
               
        }