Cannot download files/images from uploads folder in asp.net

i explain my issue here  

i got a function that should download this as

private void downloadAnImage(string strImage)

 { 

Response.ContentType = "image/jpg"; 

Response.AppendHeader("Content-Disposition", "attachment; filename=" + strImage); 

Response.TransmitFile(strImage); Response.End();

 }

and i call this function from link button as

protected void lnkDwnSlc_Click(object sender, EventArgs e) 

{ 

if (Session["slc_filepath"] != null) 

{ string path = Server.MapPath(Session["slc_filepath"].ToString());        

  downloadAnImage(path); 

} 

}

where Session["slc_filepath"] is path stored in session

but after running this code file/image is not downloading and I got no error about why file is not downloading. And I checked file path by using breakpoint , it is correct,

I search a lot form google but i can't understand where I missed something.

EDIT: on page load event i pull records from table there i saved path of file and in session i store it like

Session["slc_filepath"] = dt.Rows[0]["UploadSLC"].ToString();

where UploadSLC is column name of table where i store path of image and in database string is looking as

~\uploads\ab071770-473a-4e1a-8cfc-addeccf565d5.jpg