PictureBox控件的问题

Question

我有图像文件，我想裁剪并加载到picturebox。当我远程下载它 - 一切正常，但是当我从本地机器加载它时 - picturebox图片拉伸......

 var img = (Bitmap) Image.FromStream(new WebClient().OpenRead("https://i.snag.gy/MjJca5.jpg"));

  img = CropImage(img);

  BackgroundImage = img;
  BackgroundImageLayout = ImageLayout.Zoom;

  public Bitmap CropImage(Image img) {
   // create a graphic path to hold the shape data
   GraphicsPath path = new System.Drawing.Drawing2D.GraphicsPath();
   var points = new Point[] {
    new Point(85, 1111), new Point(934, 1111), new Point(934, 952), new Point(1642, 952),
     new Point(1642, 2000), new Point(85, 2000), new Point(85, 1111)
   };
   GraphicsPath gp = new GraphicsPath();
   gp.AddPolygon(points.ToArray());

   Bitmap bmp1 = new Bitmap(2220, 2220);

   using(Graphics G = Graphics.FromImage(bmp1)) {
    G.Clip = new Region(gp);
    G.DrawImage(img, 0, 0);
    bmp1.Save("axi.jpeg");
    return bmp1;
   }
  }

此代码返回此图片。一切正常

但是此代码返回此图片。

 FileStream file = new FileStream(openFileDialog1.FileName, FileMode.Open);
    var img = (Bitmap) Image.FromStream(file);

    img = CropImage(img);
    pictureBox1.BackgroundImage = img;
    pictureBox1.BackgroundImageLayout = ImageLayout.Zoom;
...