This is spawned from the related thread Mixed content message due to Gravatar image.

The Gravatar Cache plugin stores files without a file extension. By default, IIS does not serve extensionless files and returns a 404 to the browser. However, one can get around this by adding a wildcard mime type to web.config:

<staticContent>

 <mimeMap fileExtension="." mimeType="image/jpg" />

</staticContent>

However, this is a risky move because it is an application wide setting that tells IIS to serve all extensionless files as a JPG image. It may break other behavior that depends on the original IIS settings. It is also unknown if all Gravatar cache files are actually stored as JPGs. Finally, I may encounter other plugins that require extensionless files to be served with a different content type (e.g. text/problem-with-post-edit-buttontml).

I am not comfortable making such a big change just to get the plugin to work. Unfortunately, turning off the plugin isn't a good option either because it causes mixed content warnings when run on an SSL site.

The problems all go away if you store the file with its extension (e.g. file.jpg). Is this possible?

Thanks,

Roger