Transition to height:auto on replaced elements

dabblet.css

/**
 * Transition to height:auto on replaced elements
 * CSS brain teaser: If transitions to/from height:auto don’t work, why is the height transitioning here? 
                     And why is it not transitioning when it shrinks but only when it grows?
 */

img {
	width: 0; height: 0;
	transition: 1s linear;
	
}

div:visited img {
	width: 0; height: 0;
	transition: 1s linear;
	
}

div:hover img {
	width: 200px; height: auto;
	
}

dabblet.html

<div>
	<p>Hover over here</p>
	<img src="http://placekitten.com/400/300" />
</div>

dabblet.js

// alert('Hello world!');

settings.json

{"view":"split","fontsize":"100","seethrough":"","prefixfree":"1","page":"all"}