how to call the path of different images using a variable from a images folder

Hi,
I'am Developing a  commercial website using vs2005 and sql,in which i want the users to download wallpapers which is available in my webpage.so for each image i want to use a download button control at the bottom of the image.so wen the user clicks the button the download dialog box should appears.
the images are kept in the images folder.

the code given below is for a single image,
Protected Sub ImageButton1_Click(ByVal sender As Object, ByVal e As System.Web.UI.ImageClickEventArgs) Handles ImageButton1.Click
        Response.Clear()
        Response.AddHeader("content-disposition", "attachment;filename=Pls_Wait.jpg")

        Response.ContentType = "image/jpg"
        Response.WriteFile(Server.MapPath("~/Images/Pls_Wait.jpg"))
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