JSFiddle - React, Tailwind, and code Playground

HTML

<img src="http://vignette1.wikia.nocookie.net/houseofnight/images/8/8b/Cats.jpg/revision/latest?cb=20130812053537" alt="">
<img src="http://www.cats.org.uk/uploads/images/pages/photo_latest14.jpg" alt="">

CSS

img {
  margin: 3px;
  outline: dashed 2px gray;

  width: 200px;
  height: 200px;

  object-fit: contain; /* all magic here */
}