@mareksgregs it´s easy
let´s go
1 - Open Header.php on Frisco Theme
2 - Search <h1 id="logo" role="banner"><a href="<?php echo home_url(); ?>" title="<?php _ex( 'Home', 'Home page banner link title', 'buddypress' ); ?>"><?php bp_site_name(); ?></a></h1>
3 - Change to <h1 id="logo" role="banner"><img border="0" src="IMAGE URL" width="0" height="0"></h1>
Ok?