Responsive banner

Hallo everybody,

I use your theme ?make“ and find it very attractive.

The images used in the banner are for some reason not responsive on smaller devices , if the size is i.e. 1920×650.

That means, if I look at them on my widescreen, the banner looks perfect. On smaller screens the images are cut off on the left and right outer edges.

There are no setting opportunities to fix this. Please give me an idea, how to solve this problem. Many thanks.