Plugin and vendor images are now also precompiled

config/application.rb

@@ -41,5 +41,8 @@ module AgendaDuLibreRails
     config.action_dispatch.default_headers['X-Frame-Options'] = 'ALLOWALL'
 
     config.active_record.raise_in_transactional_callbacks = true
+
+    # In rails 4, plugin and vendor images need to be precompiled
+    config.assets.precompile += %w(*.png *.jpg *.jpeg *.gif)
   end
 end