我已按照here给出的步骤进行操作，但图片未上传。
以下是服务器的日志： -
Started GET "/pics/thumb/missing.png" for 127.0.0.1 at 2014-10-14 16:53:22 +0530
ActionController::RoutingError (No route matches [GET] "/pics/thumb/missing.png"):
actionpack (4.1.2) lib/action_dispatch/middleware/debug_exceptions.rb:21:in `call'
actionpack (4.1.2) lib/action_dispatch/middleware/show_exceptions.rb:30:in `call'
railties (4.1.2) lib/rails/rack/logger.rb:38:in `call_app'
railties (4.1.2) lib/rails/rack/logger.rb:20:in `block in call'
activesupport (4.1.2) lib/active_support/tagged_logging.rb:68:in `block in tagged'
activesupport (4.1.2) lib/active_support/tagged_logging.rb:26:in `tagged'
activesupport (4.1.2) lib/active_support/tagged_logging.rb:68:in `tagged'
railties (4.1.2) lib/rails/rack/logger.rb:20:in `call'
actionpack (4.1.2) lib/action_dispatch/middleware/request_id.rb:21:in `call'
rack (1.5.2) lib/rack/methodoverride.rb:21:in `call'
rack (1.5.2) lib/rack/runtime.rb:17:in `call'
activesupport (4.1.2) lib/active_support/cache/strategy/local_cache_middleware.rb:26:in `call'
rack (1.5.2) lib/rack/lock.rb:17:in `call'
actionpack (4.1.2) lib/action_dispatch/middleware/static.rb:64:in `call'
rack (1.5.2) lib/rack/sendfile.rb:112:in `call'
railties (4.1.2) lib/rails/engine.rb:514:in `call'
railties (4.1.2) lib/rails/application.rb:144:in `call'
rack (1.5.2) lib/rack/lock.rb:17:in `call'
rack (1.5.2) lib/rack/content_length.rb:14:in `call'
rack (1.5.2) lib/rack/handler/webrick.rb:60:in `service'
/home/stark/.rvm/rubies/ruby-2.0.0-p481/lib/ruby/2.0.0/webrick/httpserver.rb:138:in `service'
/home/stark/.rvm/rubies/ruby-2.0.0-p481/lib/ruby/2.0.0/webrick/httpserver.rb:94:in `run'
/home/stark/.rvm/rubies/ruby-2.0.0-p481/lib/ruby/2.0.0/webrick/server.rb:295:in `block in start_thread'