how do I get a parent's parent album name ?

Can someone help ?

got it my self thanks : $_zp_current_album->getParent()->getParent()->name

You should actually review the zenphoto object model. But I will save you some time.

$parent = $album->getParent() will give you the parent of an album. Of course, there may not be a parent (if it is a root level album.) In that case you will get NULL.)

Of course, $parent will itself be an album so [drum roll] $grandparent = $parent->getParent() the album's parent's parent.

From there you just use the getFolder() method for the folder name.

If you actually wanted to get the toplevel album to a subalbum there is also
http://www.zenphoto.org/documentation/functions/_functions.php.html#functiongetUrAlbum