I added line
$thumb_list[$i]['pid'] = $row['pid'];
on 1865 in functions.inc.php (function display_film_strip())
and now I can use $thumb['pid'] in function theme_display_film_strip() in my theme.
I hope, next release CPG will't contain this bug.
I won't call it a bug. 'pid' was not needed in theme_display_film_strip function and hence it was not added to $thumb array in functions.inc.php . You are modifying theme_display_film_strip as per your needs and you need 'pid' for your specific case. So how can this be called a bug?