In Print -> Image settings, the Center selection is reset when scaling the size.
In the Print menu, under Image Settings, the preference for setting the Position to Center = Both is reset to None when I apply resizing afterwards with the scaling bar or the width and height values (It even fails in more ways).
I looked at the relevant functions in src/eog-print-image-setup.c and it seems to me that if does not fit with my user expectation (I checked commit 900c32c3 ). To me it looks logical that given the variables center, scale, left, right, top, bottom, width and height the following actions take place:
on_center_changed:
if center == none do nothing
if center == horizon then modify left and right
if center == vertical then modify top and bottom
if center == both then modify left, right, top and bottom
on_scale_changed:
if center == none then modify right and bottom
if center == horizon then modify left, right and bottom
if center == vertical then modify right, top and bottom
if center == both then modify left, right, top and bottom
on_left_value_changed:
if center == none then modify left and right
if center == horizon then modify left and right and set center = none
if center == vertical then modify left and right
if center == both then modify left and right then center = vertical
...
on_width_value_changed:
modify width, height and scale
...
If you agree, I can try to write some code which actually does this.