Uploading an image to a website using handler

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C#

ASP.NET

Hi, I am trying to upload an image to a website, but I am not successful. I want to read the path of the picture in handler method from somewhere... I used Session, but in the handler the Session is null, even when I write something to the Session in a Page_Load of a page where is a button, which starts the handler or when I write it to the button_click method it still null.
I want to know, how can I give the Path of the image to the handler and how the code will looks like.

I have something like this, but it's unuseable and when I write some path of an existing image to parameters of the Write Method it downloads the handler, but I don't want it. I want to upload an image, which I choose to the website, does anyone know how? Thanks for replies!

public void ProcessRequest (HttpContext context) {
        context.Response.ContentType = "image/jpeg";
        string savedFileName = "";

        foreach (string file in context.Request.Files)
        {
            HttpPostedFile hpf = context.Request.Files[file] as HttpPostedFile;
            if (hpf.ContentLength == 0)
                continue;
            savedFileName = context.Server.MapPath(context.Session["FileUpload"].ToString());
            hpf.SaveAs(savedFileName);
        }
        context.Response.Write(savedFileName);
    }