Never mind, I got it working perfectly with max-width, the first method you recommended.
My question was the following:
Let’s say I want to modify .featured-image-wrapper, but I dont want my change to be applied everywhere, just in a few specific places. Is it possible to create a “copy” of .featured-image-wrapper that has all the same properties, but changes a few?
Create a class called “my-pretty-image” that “inherits” all of .featured-image-wrapper’s properties, but changes a few?