How to show the download Popup when we click on the button? Add this code in Button Click Event Protected Sub btnExportToImage_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnExportToImage.Click { Response.ContentType = "png" Response.AppendHeader("Content-Disposition", "attachment; filename=TopIndustry.png") Response.TransmitFile(Server.MapPath("~/TempImageFiles/" + Session("ImageName").ToString())) Response.End() } - Image is stored on the server. - so in this example image name is set on runtime and stored in to the session. - On button click End Sub It will show the Output: