How to implement img smaller side resizing?

Question

css

Good evening!
Given:
1. DIV with dimensions 100x100px and overflow: hidden;
2. img inserted into a DIV of indefinite size (clearly larger than 100x100px).
What you need: It is
necessary that the image completely fills the entire existing div while maintaining its proportions.
If img has a width > height, then the height becomes 100px, while the width adapts proportionally and some part of it that crawls out of the div area is not visible.
If img has width < height, then the width becomes 100px, the height adapts... and so on.
What exactly is needed:
So that the size of 100px is assigned to the smaller side of the img.
Thanks in advance for any help.
Sincerely,
Alexander.

Answer 1

jsfiddle.net/iiil/6uTMX/1

Answer 2

What if it's simple
?