When you create a custom recovery image, recimg will store it in the specified directory, and set it as the active recovery ...

When you create a custom recovery image, recimg will store it in the 
specified directory, and set it as the active recovery image. If a custom 
recovery image is set as the active recovery image, Windows will use it when
you refresh your PC. You can use the /setcurrent and /deregister options to
select which recovery image Windows will use. All recovery images have the 
filename CustomRefresh.wim. If no CustomRefresh.wim file is found in the 
active recovery image directory, Windows will fall back to the default image 
(or to installation media) when you refresh your PC.