当我的应用在浏览器中显示页面时，我在Rails 4服务器日志中看到以下错误。
我发现在其他页面上也会发生这种情况，只要有图像。
错误日志：
Started HEAD "/assets/login_header-117f87e381545e9f6d5a7accb7aa72188a0304644af6891c42e1cd57f38fad67@2x.jpg" for 127.0.0.1 at 2016-02-26 12:31:54 -0500
ActionController::RoutingError (No route matches [HEAD] "/assets/login_header-117f87e381545e9f6d5a7accb7aa72188a0304644af6891c42e1cd57f38fad67@2x.jpg"):
actionpack (4.2.2) lib/action_dispatch/middleware/debug_exceptions.rb:21:in `call'
actionpack (4.2.2) lib/action_dispatch/middleware/show_exceptions.rb:30:in `call'
railties (4.2.2) lib/rails/rack/logger.rb:38:in `call_app'
railties (4.2.2) lib/rails/rack/logger.rb:20:in `block in call'
activesupport (4.2.2) lib/active_support/tagged_logging.rb:68:in `block in tagged'
activesupport (4.2.2) lib/active_support/tagged_logging.rb:26:in `tagged'
activesupport (4.2.2) lib/active_support/tagged_logging.rb:68:in `tagged'
railties (4.2.2) lib/rails/rack/logger.rb:20:in `call'
request_store (1.3.0) lib/request_store/middleware.rb:9:in `call'
actionpack (4.2.2) lib/action_dispatch/middleware/request_id.rb:21:in `call'
rack (1.6.4) lib/rack/methodoverride.rb:22:in `call'
rack (1.6.4) lib/rack/runtime.rb:18:in `call'
rack (1.6.4) lib/rack/lock.rb:17:in `call'
actionpack (4.2.2) lib/action_dispatch/middleware/static.rb:113:in `call'
rack (1.6.4) lib/rack/sendfile.rb:113:in `call'
railties (4.2.2) lib/rails/engine.rb:518:in `call'
railties (4.2.2) lib/rails/application.rb:164:in `call'
rack (1.6.4) lib/rack/content_length.rb:15:in `call'
thin (1.6.4) lib/thin/connection.rb:86:in `block in pre_process'
thin (1.6.4) lib/thin/connection.rb:84:in `catch'
thin (1.6.4) lib/thin/connection.rb:84:in `pre_process'
thin (1.6.4) lib/thin/connection.rb:53:in `process'
thin (1.6.4) lib/thin/connection.rb:39:in `receive_data'
eventmachine (1.0.9.1) lib/eventmachine.rb:193:in `run_machine'
eventmachine (1.0.9.1) lib/eventmachine.rb:193:in `run'
thin (1.6.4) lib/thin/backends/base.rb:73:in `start'
thin (1.6.4) lib/thin/server.rb:162:in `start'
rack (1.6.4) lib/rack/handler/thin.rb:19:in `run'
rack (1.6.4) lib/rack/server.rb:286:in `start'
railties (4.2.2) lib/rails/commands/server.rb:80:in `start'
railties (4.2.2) lib/rails/commands/commands_tasks.rb:80:in `block in server'
railties (4.2.2) lib/rails/commands/commands_tasks.rb:75:in `tap'
railties (4.2.2) lib/rails/commands/commands_tasks.rb:75:in `server'
railties (4.2.2) lib/rails/commands/commands_tasks.rb:39:in `run_command!'
railties (4.2.2) lib/rails/commands.rb:17:in `<top (required)>'
bin/rails:8:in `require'
bin/rails:8:in `<main>'