Featured Blog Image is Cut on the Left

Hi There! We’re facing an image problem, like this one:

The featured image seen here is 850*478 in dimension.
I have a CSS code in the Custom CSS section like this:

.post .pic {
width: auto;
height: 500px;
}

Somehow some images are cut on the left side, and we can not correct it.
What can we do?

Thank you.

BK