Resizing Banner Pictures

Site URL: https://www.newvisionresearch.org

Hi - I am trying to get a few banner pictures to resize as oppose to being cropped or zoom in the pages with banners.  I am not a coder and my skills are fairly basic when it comes to css.  Can anyone help me with this?  If you go to the other pages under the about index you can see the same issue happening where some of the peoples faces get cut off. 

example attached. 

By the way - my image is 1500 pixels wide and about 500kb following the squarespace best practice for picture uploads

Add to Home > Design > Custom CSS

.banner-thumbnail-wrapper img {
    width: 100% !important;
    height: auto !important;
    top: 0 !important;
}
.banner-thumbnail-wrapper {
    min-height: 350px !important;
}

@tuanphan Thank you, it kind of works but then this happens 

(see picture)

the pictures respond to the width but there's a weird gray background

Can you share link to page in screenshots?

@tuanphan is this what you mean?

url is:  www.newvisionresearch.org 

29 minutes ago, NewVisionResearch said:

@tuanphan is this what you mean?

 

url is:  www.newvisionresearch.org 

 

I don't see grey image on the above link?