I mean this:
I have these images of the car: front, back, left, right, top. "Back" image is always hidden I only make it visible when I work with back of the car and hide "front". I can not make front and back both visible at the same time, because they messed up.
So having this situation I want to switch on /off images, but keep "back" image always hidden, That is why I assumed that changing transparency can work here.