Post image shares same class as featured image does

When I create an image in a post it shares the same class as my featured image. How do I differentiate it to edit it with CSS Hero? I’m using Divi and the in post added images have the same descriptor Left-area content images. Whats the way I can differentiate the featured image from those I add to the posts?
I went into the wordpress editor and input a new class on the in post image and tried to select it with css hero it doesnt recognize and differentiate it from the featured image. ARe you guys able to help on this?