Experimenting with a Nunjucks shortcode for images in Eleventy

img.njk

<!-- throws an error, missing [alt] attribute -->
{% img src="img/9a93578a.png", loading="lazy" %}

<!-- local img source, outputs a standard <img> tag -->
{% img src="img/9a93578a.png", alt="zachleat’s Avatar", loading="lazy" %}

<!-- remote img source -->
<!-- download using avatar-local-cache, outputs <picture> with webp and png fallback -->
{% img src="https://www.gravatar.com/avatar/e1899004c71c7043343196103e210be3?default=404", alt="zachleat’s Avatar", loading="lazy" %}