Gallery images on mobile too big-wrong orientation than site (need horizontal)

Site URL: https://www.anitaclarkdesign.com

I switched out gallery images (resized, etc) from vertical images to horizontal images. However, they are not looking good on mobile at all. Client is complaining. Is there anything we can do to make the gallery look good on mobile??I have tried some CSS, but it's not working.  I would like to add more height to the gallery--not more width.

Using Version 7.0– Brine family (Foster Juice Co. template)