How to make an inner shadow for a small image without specifying its size?

Question

css

Tell me how to darken a small image around the edges.
With absolute positioning, the box-shadow stretches to fit the width of the screen and doesn't look great:
codepen.io/anon/pen/zvBqXv

Answer 1

Found a solution.
You need to add display: inline-block; to the img selector.

Answer 2

Add to .img {
position: relative;
width:200px;
}
codepen.io/anon/pen/KdMzjL
?
Or do you need to darken the image itself? )