Visualization in Body scanning?

Should one visualize while scanning different parts of the body? If not, should one try to suppress it? When I do body scanning practice, automatically an image of the corresponding body part arises in my mind. In fact, every single time when I am changing attention from a part to another it is the mental image of that part that arises first and sensations after that (if any). I have a hunch that this is not the right practice. I tried to "stop" it, but I could not...and hence the question. Can you give your insight on this? Also please share a method to avoid visualizing automatically (if that is indeed correct).