Performance FileResultPath (path to image) in Asp.Net MVC?

I have an Mvc action that sends "FilePathResult" for the image "jpeg"as shown below.

public ActionResult GetImage()
        {
            string outputImagePath = Server.MapPath(@"Images/OutputImage.jpeg");
            return File(outputImagePath , "image/jpeg");
        }

Now it takes significantly longer compared to linking to the image path using direct Url . The time shown below is shown below.

http: // WebSite / Controller / GetImage takes 500 ms

http: //WebSite/Images/OutputImage.jpeg takes 10 ms

Is this normal, or am I missing something?

Update: This is an average time. I am using the following environment.

.Net 4, Asp.Net 2.0, IIS 7.5, Ninject