Preview is closed in Mavericks when last window is closed
You need to disable Preview's automatic termination.

defaults write com.apple.Preview NSDisableAutomaticTermination -bool TRUE &amp;&amp; killall -HUP Finder


This is due to Lion's automatic termination which was introduced so that apps which have no windows open and are not performing a task can be quit to save system resources. Generally it's good to leave on, but if you really want to disable it, use the above command.

You can disable automatic termination in all apps by setting it in the global preferences.

defaults write -g NSDisableAutomaticTermination -bool TRUE &amp;&amp; killall -HUP Finder