This plugin from WPZA provides your website with a shortcode to display AMP images, rather than using the standard HTML img tags in WordPress.
After installing this plugin, you must use the shortcode [amp-img] on any page you would like the amp-img tag to be displayed on.
To insert the image, you must use the image attribute as such:
[amp-img image="
https://wpza.net/example-image.jpg"]
To insert the alt text, you must use the alt attribute as such:
[amp-img image="
https://wpza.net/example-image.jpg" alt="Example image alt text"]
