Pass Values from a user control to a web form

Hi All, 

I am currently trying to add captcha to my webform.

I have a question on how to pass a number/string from a .ascx to a .aspx page.

The aspx is being used in the .ascx (user control) in an image tag.

<asp:Image ID="imgCaptcha" runat="server" ImageUrl="Image.aspx"/>

The aspx page is being rendered as a jpeg image. So Inorder for the captcha to be displayed with the image, I need to pass the code from the user control to the aspx page.

I have an option to pass the number as a que ...