zeo

Dump this code anywhere in Theme’s template functions.php file (For example, functions.php file for a Theme named “default” would probably reside in the directory wp-content/themes/default/functions.php):

add_filter('gallery_style',
        create_function(
                '$css',
                'return preg_replace("##s", "", $css);'
                )
        );

And these are the classes for your stylesheet:

.gallery {}
.gallery-item {}
.gallery-icon {}
.gallery-caption {}