Heads getting chopped off in Alto

I like the minimalist Alto theme but the images posted in “Post Image” are getting cropped into squares without any way for me to specify how they’ll be cropped.

I need to educate myself on CSS but it looks like this may be driving it?

.u-object-fit {
height: 100%;
-o-object-fit: cover;
object-fit: cover;
width: 100%;

If I turn off the width, it appears that the image will not be cropped?

Anyway, how do I prevent the cropping via code injection?