Glad to hear you're liking the new version!
With the new SCLogin module, there's an option for "Button Type" where you can select Javascript, Image, or Text. With that, you can specify a completely custom image for the login button if you'd like.
Alternatively, if you're using the {JFBCLogin} tag, you can use the following HTML for your own image:
<a href="javascript:void(0)" onclick="jfbc.login.login_custom();"><img src="/path-to-button-image.jpg"/></a>
Hope that helps, but if not, let me know!
Alex