It seems there's a big canonical issues with Nextgen Galery.
All url created with adding the album/galery shortcode in page content have a bad canonical. All canonical for galery / image url are on the root page.
Have canonical on :
which prevent the search spider to index all albums pages.
I have removed all canonical for page directly form class-frontend.php, but a help to correct it in a more cleaner way would be appreciated