captcha image being blocked by IIS

I'm implementing captcha on my website like the one in https://web.ar开发者_开发百科chive.org/web/20210304122904/https://www.4guysfromrolla.com/articles/060706-1.aspx. It is working fine while running on VS2008. However, not when uploaded on IIS. I think the image is being blocked by IIS.. anyone knows how to fix this?

thanks

Fixed it.. Issue with .net 4.0 http handler has to be included in system.webserver instead of system.web in web.config.

Thanks to:

http://www.codeproject.com/KB/custom-controls/CaptchaControl.aspx?msg=2117617 (Sectio: Image not displaying - IIS7).