Yep, carre is correct. The module decides its own height and width based on the slide pictures you use (basically the largest picture is taken into account).
There is no "fixed" value for sizing, because the slider is "responsive". (it shouldn't have any fixed value though)
Instead of "fixed" values, you should use "max-height" and "max-width" values if you insist to resize the slider manually.
To do it, you need to use CSS;
img.rs-slide-image {
max-height:300px !important;
}
This CSS rule will limit the slider to have Max. 300 pixel height and the width will be "automatic". You can apply the same idea for width as well, then you need use
max-width: 300px !important;
For better usage; all the slide pictures
must have the same resolution
Case solved. Topic is closed.