Salut,
En script gratuit, va vers:
4Images Gallery:
Short description: An Image Gallery system featuring unlimited categories/subcategories, web-based and FTP images upload, auto-thumbnails, comments, send a picture, rate a picture, random pictures, extensive administration panel.
Homepage: http://www.4homepages.de/
ou Coppermine Photo Gallery
Short description: An Image Gallery system featuring categories and albums, thumbnails and intermediate size pics, search feature, new and random pictures, user management (private galleries, groups), user comments, e-cards feature, slideshow viewer.
Homepage: http://coppermine.sourceforge.net/
et pour le payant, je ne connais que photopost, mais ce dernier est souvent intégré en tant que forum.
Il en existe plein d'autres, via google
Bon weekend,
Francois