The <img> tag displays an image on the page. It's self-closing (no </img>) and relies on attributes to know what to display:
<img src="logo.png">The src attribute points to the image file - it can be a local file or a full URL. Without src, the tag is useless.
Without size attributes, the image renders at its full resolution, which can take over the entire page. Use width and height to control it:
<img src="dashboard.png" width="400" height="300">You can set just width and the height adjusts automatically to keep the proportions. Later with CSS, you'll have more control over sizing, but these attributes work for quick prototyping.
One of the nice things about HTML is that tags compose naturally. Want a clickable image? Wrap the <img> inside an <a> tag:
<a href="https://learnlwc.com">
<img src="logo.png" width="200">
</a>Now clicking the image takes you to the link. Not every combination makes sense (wrapping an image in <b> won't make it bolder), but most tags work together the way you'd expect.
This composability matters for LWC too. Components are built by nesting elements inside each other, and understanding how HTML tags combine is the foundation of that.