differen image planes

How can I set up 2 different image planes for side and front view? If I set a image plane it shows in all views

simply split the view (move the mouse to the upper 3d-view border, middle click and press split, then click left)

in one view press numpad 3 for side view, in the other numpad 1 for front view. then each view can have it’s own background picture.