Hi, you have to build a div with padding in percent and relative. Then you set the div in it absolute and width and height to 100%.
Example:
slider 960px x 300px
300*100%/960 = 31.25%
my slider.css line 1 and 2
.promo_slider_wrapper { margin:0 0 0 0; position:relative; padding-top: 31.25%;}
.promo_slider { overflow:hidden; position:absolute; top: 0; width: 100%; height: 100%;}
This works. If you found some static hight,you have to remove it.