Allow Relative URL for Login Image Use (or https://)

Hi,

I was wondering there is a way to allow the login image URL to be relative or to allow https:// ?

I've tried both a relative URL for my image as well as changing http:// to https:// but it keeps reverting back to http:// on save.

The reason I ask is because I am serving my login page (and admin dashboard) over SSL and the login image on the login page isn't "securely served/called over SSL" so the page throws an SSL warning.

Thanks