Get Magento config information

I'm trying to get the base url and the media directory from the Magento configuration and I'm try开发者_JAVA百科ing to use them for a template that has images. I've only gotten as far Mage::getConfig(). I'm not sure what to do next...

Mage::getBaseDir ($type='base')

http://freegento.com/doc/d8/dcb/class_mage.html#7c9023c03db151ba782ec95ab289f2fe

Or also

<?php echo Mage::getURL('customerfolder/subfolder')."images/payment_types.gif" ?>

This will return would return http://www.yourdomain.com/customerfolder/subfolder