C# 后台处理图片的几种方式

第一种： 将上传图片直接保存到本地

 var supportedTypes = new[] { "jpg", "jpeg", "png", "gif", "bmp" };
                    var fileName = System.Web.HttpContext.Current.Request.Files[0].FileName;
                    var fileExt = System.IO.Path.GetExtension(fileName).Substring(1);
                    if (!supportedTypes.Contains(fileExt))
                    {
                        return Json(new { msg = -1 });
                    }

                    Random r = new Random();
                    var filename = DateTime.Now.ToString("yyyyMMddHHmmss") + r.Next(10000) + "." + fileExt;
                    var filepath = Path.Combine(Server.MapPath("~/avatar/temp"), filename);
                    head.SaveAs(filepath);

第二种：将图片转换为byte 类型

//filePath 图片物理地址
FileStream fs = new FileStream(filepath, FileMode.Open);
                    byte[] byData = new byte[fs.Length];
                    fs.Read(byData, 0, byData.Length);
                    fs.Close();

第三种：将上传图片转换为byte 类型

              HttpPostedFile file = System.Web.HttpContext.Current.Request.Files[0];

                if ((file == null))
                {
                    return Json(new { Success = false, Msg = "上传图片失败", Path = "" });
                }
                else
                {
                    System.Drawing.Image image = System.Drawing.Image.FromStream(file.InputStream);

                    MemoryStream ms = new MemoryStream();
                    image.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);

                    byte[] byteData = new byte[ms.Length];
                    ms.Position = 0;
                    ms.Read(byteData, 0, byteData.Length);
                    ms.Close();
                    image.Dispose();

                 
                }
            }