Alias of <file> as a more semantic means of saving images to WordPress.
See File for documentation on supported attributes.
featured : Automatically sets the node name with the value '_thumbnail_id'. This provides a shorthand for saving images as the 'featured image' of a post.
<img src="./images/penguin.jpg" alt="Penguin!" />
<post>
<title>Just another post about penguins</title>
<img src="./images/penguin.jpg" alt="Penguin" featured />
</post>