Stay in HTTPS when explicitely set?

[Nils]

Right now when I access my page via HTTPS all the links still point to the HTTP site, so as soon as I click somewhere I am back to the unencrypted connection. Also, the page is marked as insecure because the images are still served via HTTP.

Wouldn't it be possible to detect if the forums have been accessed by HTTPS and automatically correct the image and base URLs when this is the case?

I think something like this in the conf_global.php might already be a start, but I'm not sure what kind of subtle bugs this might introduce, for example if URLs are put into the cache:

if($_SERVER['HTTPS']) {

    $INFO['board_url'] = str_replace('http://', 'https://', $INFO['board_url']);

}