If you're running a DotNetNuke site on Windows Server 2008 with IIS 7, there are some great new features you can use. In fact, you'll see some of them in use on this site, like the ability to have extensionless URLs. In order to achieve the extension-less URL effect1, I had to switch my server from classic mode to integrated mode, and this switch caused the Captcha images throughout the site to stop working. Here's how to solve this problem.
It turns out that the solution is easier than I thought.
When you switch to integrated mode in IIS 7, the HTTP handlers are now defined in a different location in web.config. You can leave the handlers defined in the httpModules section under system.web. But any of these handlers that you want to have configured for IIS when running in integrated mode need to also have entries under the new system.webServer node as follows:
(click to enlarge)
There's probably a commented section in web.config that I missed. Either way, here's the fix for Google to index and hopefully you to find if you're wondering like I was what happened to my Captcha images.
1
This effect is also made possible by the use of the URL Master module from iFinity, which I highly recommend.