<title> tag with Alt & Title Text / Description instead of Picture# ?

Hi, on individual image pages in galleries, I’m trying to make our <title> tags (already re-written using AIOSEO) be something like:

<title=”Alt & Title Text / Description << Galleryname | Sitename”>

instead of the way NGGallery is currently re-writing them as:
<title=”Image # << Galleryname | Sitename”>

Looking in /lib/rewrite.php it feels like lines 186/187 should be all I need to edit:

if ( !empty($pid) )
$new_title .= __(‘Picture’, ‘nggallery’) . ‘ ‘ . $pid . $sep ;

But not sure how to load up variables at line 167 with the Alt /Description like:

$pid = get_query_var(‘pid’);

What are the variable names to query with from wp_query? is there ‘description’? or ‘meta’? How could I find these?

Sorry, it might be totally obvious but I just can’t seem to find it!
Thanks for any help…