How to configure a i-rule with image (company logo) on it

What about this?

when HTTP_REQUEST {       
    if { [active_members ] < 1 } {
        switch [string tolower [HTTP::uri]] {
            "/maintenance/logo.gif" {
                HTTP::respond 200 content [b64decode "Base64 decoded Image string"] "Content-Type" "image/gif"
            }
            "/maintenance/index.html" {
                HTTP::respond 200 content "html-code of the sorrypage (escape all ")"
            }
            default {
                HTTP::redirect "https://[HTTP::host]/maintenance/index.html"
            }
        }
    } elseif { [string tolower [HTTP::uri]] eq "/maintenance/index.html" } {
        HTTP::redirect "https://[HTTP::host]"
    }
}

If you are using external CSS or even JavaScript files, we prefer to include everything in a single HTML-file. For the image you can also use something like this:

Hope that helps you and/or point you in the right direction.

Ciao Stefan 🙂