We have been testing Joomla! with our requirements
- User friendly back-end e.g. easy to add new wallpapers to the site
- Gallery / Images plugin or build in CMS with various display and settings options
- Comment / Rating system e.g. for user to give comment / rate the wallpapers
- User-levels to control user-access to different features e.g. easy to add user with different user-levels
- Flexible and extensible CMS which can grow with us
- Active community & support with good documentation
After installing Joomla! I went straight to the back-end. At first I would not say that Joomla! back-end is user friendly. It take times to fully understand how it works and is build up. Joomla! CMS is build around articles. So the first solution we would have to find the best possible way of adding new wallpapers to the site.
There are lots of good extension for Joomla regarding photos and images. But one extension caught my eyes: Simple Image Gallery. It provide a simple plugin tag like {gallery}myphotos{/gallery}. This plugin can turn any folder of images located inside your Joomla! website into a grid-style image gallery with cool lightbox previews. The best part is that it would allow us to add wallpapers direct into the article system. For 15 Euros it is possible to buy PRO version of this extension which offer great more features.
Joomla! has inbuilt rating system for articles, that is registered user can rate each article/wallpaper we would publish on our site.
The new release of Joomla! 2.5 offer great user-levels to control user-access to different features.
Joomla! is flexible, extensible and can grow with us.Joomla! community, support and documents are good.
Roundup regarding Joomla!. Joomla meets all our requirement. Same as with Drupal and WordPress we would have to dig into programming to get the results we would like. WordPress, Drupal or Joomla would not be used out of the box.