With only the parent div and the child img elements as demonstrated below how do I vertically and horizontally center the img element while explicitly not defining the height of the parent div?
<div class="do_not_define_height"><img alt="No, he'll be an engineer." src="theknack.png" /></div>I'm not too familiar with flexbox so I'm okay if flexbox itself fills up the full height, but not any other unrelated properties.