How To Rotate An Image In .NET

I have an asp.net 2010 project. I write a jpg to the filesystem. Then I display it in an Image control. Then I use this code on button click to allow the user to rotate it 90 degrees.

string path = Server.MapPath(Image1.ImageUrl) ;
// creating image from the image url
System.Drawing.Image i = System.Drawing.Image.FromFile(path);
// rotate Image 90' Degree
i.RotateFlip(RotateFlipType.Rotate90FlipXY);
// save it to its actual path
i.Save(path);
// release Image File
i.Dispose();

It does rotate (I can actually watch that happen in Windows Explorer). But when I run the app again and it grabs the file from its path, it still displays it in its original form.