help with choosing a theme.

For users to upload pictures and rating you need the functionality of plugins rather than a specific theme.

See if the Roles and Capabilities system built into WordPress would work for your situation http://codex.wordpress.org/Roles_and_Capabilities

Otherwise look utilizing contact form plugins for user submitted data. For example
http://perishablepress.com/user-submitted-posts/
http://wordpress.org/extend/plugins/wordpress-guest-post/
http://www.gravityforms.com/

There are also plugins for rating