Html tag img is not valid

Bannerize pro creates images with the widht and heigth attributes in an invalid form.

This is how it is done today
<Img src="" width="100px" height="200px" alt="">

But would not the correct one be without px or% in widht and heigth attributes?
<Img src="" width="100" height="200" alt="">

Because of this problem the html does not get valid in w3c validator