JFBConnect has multiple ways to be used in a mobile app. You can use the following tag anywhere on your site to show the login buttons for specific providers, along with a custom image button (which can be optimized for mobile):
{JFBCLogin providers=facebook,twitter image=mobile_login.png}That will load the mobile_login.png button from /media/sourcecoast/images/provider/facebook/mobile_login.png and the twitter directory, respectively.
That avoids using the SCLogin altogether which gives you full control. Of course, you can use the SCLogin module instead and configure the custom login buttons in there as well as different styling options.
I hope that helps answer your question, but if you need anything else, please let me know.
Thanks,
Alex