Display image based on value from QueryString Parameter in ASP.Net

In my asp.net+vb web with access database there is a page which displays data as per query string and the string is PNO and all data is correctly displayed in gridview and dataview. there is a Image1.ImageUrl and i used the following code but it is not working

Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs)
        Dim PNO As String
        PNO = Request.QueryString("PNO")
        Image1.ImageUrl = "C:/wing/Photos/" + PNO + ".jpg"
    End Sub