Swiper Slider get broken on window resize

Hi! I am using swiper for a banner slider.
It is working fine but my problem is when I change the browser, it become messed up.
I am using chrome DEV TOOLS - Device toggle to simulate the view on mobile phones.

but when I change the view into a Iphone 6 this happens

THE IMAGE GOT MESSES AND IT BECOME VERY BIG
IT ALMOST SCATTER THE WHOLE PAGE

NOTE: I need to refresh EVERY TIME I CHANGE MOBILE VIEW to make the SLIDER work

EXPECTED OUT PUT

Looks like you haven’t set correct image size in your CSS

What do you mean? because when I try to refersh the page it works fine,

It is only been broken when changing mobile dev tool

image