Way To Create An Image Automatically On The Server After Every 5 Minutes

to create an image from some data in my database on the server every 5 minutes. The image path is Images/top5.jpg, so that users can place a link to that imagine on some forum or whatever and it will update every 5 minutes.I am doing this by using a

System.Threading.Timer in Global.asax:
vb.net Code:
Public Class Global_asax
Inherits System.Web.HttpApplication
Dim path As String
Dim timer As System.Threading.Timer
Sub Application_Start(ByVal sender As Object, ByVal e As EventArgs)
[code]...