IO流操作-图片操作（二）

一，选取一张图片

       var open = new OpenFileDialog();
            open.Filter = "图片|*.jpg";
            open.ShowDialog();
            var filepath = open.FileName;

（1）将图片转成流，流的方式生成图片
//第一中方法，先转成流
            FileStream file=new FileStream(filepath,FileMode.Open);
            //创建一个file.length大小的数组控件
            byte[] bt= new byte[file.Length];
             file.Read(bt, 0, bt.Length);
             file.Close();             //创建内存流
            MemoryStream mstream=new MemoryStream(bt);
            System.Drawing.Image image = System.Drawing.Image.FromStream(mstream);
            var imgPath = "../../IMG/2015.png";
            image.Save(imgPath, ImageFormat.Png);

（二）直接读取

  System.Drawing.Image image = System.Drawing.Image.FromFile(filepath);
            var imgPath = "../../IMG/2015.png";

（3）转成位图进行存储

    Bitmap bi=new Bitmap(filepath);
            var imgPath = "../../IMG/2015.png";
            bi.Save(imgPath);

（4）先转成流，在使用位图进行读取

 FileStream file = new FileStream(filepath, FileMode.Open);
            //创建一个file.length大小的数组控件
            byte[] bt = new byte[file.Length];
            file.Read(bt, 0, bt.Length);
            file.Close();
            //把流转换成内存流
            MemoryStream ms=new MemoryStream(bt);
            Bitmap bi = new Bitmap(ms);
            var imgPath = "../../IMG/2016.png";
            bi.Save(imgPath,ImageFormat.Png);