BuddyPress.org

@gian-ava nice writeup.
However, I would do it without editing template files if possible.
So rather than editing header.php, I’d upload the jquery.tipsy.js file to my themes js folder.
Create a new file called jquery.tipsy.tips.js and upload to the same folder, use this file to add the jquery rules that you want the tips displayed on, like

var $j = jQuery.noConflict();
$j(document).ready(function() {
$j('.item-avatar a').tipsy({gravity: 's'});
});

Then in my themes functions.php add

/* Load the Tipsy JS javascript */
function tipsy_loaded_init() {
wp_enqueue_script( 'tipsy-js', TEMPLATEPATH . '/js/jquery.tipsy.js', array( 'jquery' ) );
wp_enqueue_script( 'tipsy-js-tips', TEMPLATEPATH . '/js/jquery.tipsy.tips.js', array( 'jquery' ) );
}
add_action( 'template_redirect', 'tipsy_loaded_init' );


As for editing the BuddyPress widgets, maybe you should open a trac ticket to have title=" added to the image hrefs in bb-core-widgets.php