Filer is a REST based client/server tier for image processing and storage.  Like the rest of RGB Daily its implemented in PHP.  I have branched it from the core and plan to develop it as a separate project; potentially as an open source project.  The system is design to offload heavy weight image processing tasks asynchronously to clustered LAMP services such as those provided by Mosso or Media Temple.  So far RGB Daily is composed of the following horizonatally scalable tiers:

• Web Tier (dedicated nodes)
  
• Apache with mod_php5
• PHP with APC
• Memcached for session storage & DB query caching
• CDN for application static resources
  
• DB Tier (dedicated nodes)
• InnoDB storage engine
  
• Application Level Partitioning (still needs work)
• Filer (LAMP cloud service)
• File serving and image processing
  
• SmartStream client disconnects after URI generation but before image processing
• Intelligent file spreading for intelligent/scalable directory structure

More to come...