[Koha] Replacing Logo's in the Intranet

Hello: We've been trying to replace the Koha logo in the Intranet/Staff Client but have been unsuccessful. We've replaced: /intranet-tmpl/prog/img/koha-logo.gif /intranet-tmpl/prog/img/koha-logo-medium.gif But it doesn't seem to work. Are we doing this wrong? Thank you. Best, Gautam -- Please read our new blog at: http://blog.prathambooks.org/