C# base64 Img 互转

 [AcceptVerbs(HttpVerbs.Post)]
 public JsonResult Upload(HttpPostedFileBase fileData)
 {
 try
 {
 if (fileData != null)
 {
 string ext = Path.GetExtension(fileData.FileName).Remove(, ); // 文件扩展名
 Image img = Image.FromStream(fileData.InputStream);
 Bitmap bmp = new Bitmap(img);
 MemoryStream stream = new MemoryStream();
 bmp.Save(stream, System.Drawing.Imaging.ImageFormat.Bmp);
 stream.Position = ;
 byte[] data = new byte[stream.Length];
 stream.Read(data, , (int)stream.Length);
 stream.Close();
 string base64String = "data:" + ext + ";base64," + Convert.ToBase64String(data, , data.Length);
 return Json(base64String, JsonRequestBehavior.AllowGet);
 }
 }
 catch (Exception)
 {
 }
 return Json(null, JsonRequestBehavior.AllowGet);
 }
 public string Base64ToImg(string base64)
 {
 try
 {
 int len = base64.IndexOf("base64,") + ;
 int len1 = base64.IndexOf("data:") + ;
 string ext = base64.Substring(len1, len - len1 - );
 string filePath = "/Content/newsImg/" + DateTime.Now.ToString("yyyyMMddHHmmssfff.") + ext;
 base64 = base64.Remove(, len);
 byte[] arr = Convert.FromBase64String(base64);
 MemoryStream ms = new MemoryStream(arr);
 Bitmap bmp = new Bitmap(ms);
 bmp.Save(Server.MapPath(filePath), ext.ToLower().Contains("png") ? System.Drawing.Imaging.ImageFormat.Png : System.Drawing.Imaging.ImageFormat.Jpeg);
 ms.Close();
 return filePath;
 }
 catch (Exception)
 {
 }
 return "";
 }