With an image shift, all corners are shifted in the same direction. We assume that the skew is correct.
Change the back side if the image on the back side is shifted.
Change the front side if the image on the front side is shifted.
Measure the distance between the top-left corner on the front side and the back side in the feed direction.
Measure the distance for all the corners in the feed direction.
Measure the distance for all the corners in the direction perpendicular to the feed direction.
Calculate the average value in the feed direction (X) and the average value in the direction perpendicular to the feed direction (Z).
If the media registration is not optimal, change the value or use another setting depending on how the registration looks.