Imagine, for a moment, that your browser stopped showing you images. You would still see them referenced in articles, you’d read conversations about them, people making jokes. What would this experience be like for you? You would certainly feel pretty left out.
This decision tree describes how to use the alt attribute of the element in various situations. For some types of images, there are alternative approaches, such as using CSS background images for decorative images or web fonts instead of images of text.
I use the CSS :has() pseudo-class to provide an interactive alt text decision tree (from the W3C WAI Tutorial) that uses no script. It is progressively enhanced, so browsers without support for :has() still get all the content.