public static class Base64Helper

    {

        /// <summary>

        /// base64字符保存图片到本

        /// </summary>

        /// <param name="filePath">保存的图片完整路径</param>

        /// <param name="base64String">base64字符串</param>

        public static void Base64SaveImage(string filePath, string base64String)

        {

            try

            {

                //如果base64是通过http传过来的，要注意其中的%、，、空格等转换，C#规定base64的长度必须是4的倍数，有个别语言是2的倍数，补上==。

                base64String = base64String.Trim().Replace("%", "").Replace(",", "").Replace(" ", "+");

                if (base64String.Length %  != )

                {

                    base64String += "==";

                }

                byte[] arr2 = Convert.FromBase64String(base64String);

                using (MemoryStream ms2 = new MemoryStream(arr2))

                {

                    System.Drawing.Bitmap bmp2 = new System.Drawing.Bitmap(ms2);

                    bmp2.Save(filePath, System.Drawing.Imaging.ImageFormat.Jpeg);

                    bmp2.Dispose();

                }

            }

            catch (Exception ex)

            {

                LogHelper.WriteLog("图片保存异常：" + ex.ToString());

            }

        }

        public static string ImgToBase64String(string Imagefilename)

        {

            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 = ;

                ms.Read(arr, , (int)ms.Length);

                ms.Close();

                return Convert.ToBase64String(arr);

            }

            catch (Exception ex)

            {

                LogHelper.WriteLog("图片读取异常：" + ex.ToString());

                return null;

            }

        }

        public static string ImageToBase64(string path)

        {

            byte[] bytes = GetPictureData(path);

            string base64 = Convert.ToBase64String(bytes);

            return base64;

        }

        public static Bitmap Base64ToImage(string base64)

        {

            byte[] arr = Convert.FromBase64String(base64);

            MemoryStream ms = new MemoryStream(arr);

            Bitmap bmp = new Bitmap(ms);

            ms.Close();

            return bmp;

        }

        public static byte[] GetPictureData(string imagePath)

        {

            FileStream fs = new FileStream(imagePath, FileMode.Open);

            byte[] byData = new byte[fs.Length];

            fs.Read(byData, , byData.Length);

            fs.Close();

            return byData;

        }

    }