What is the difference between inserting an image using the <img> tag and setting a background via CSS?

The <img> tag is used to insert an image as a standalone content element on a page. It is a semantically meaningful element that browsers and search engines recognize as an image. It supports the alt attribute, which is important for SEO and accessibility.

Background images via CSS (background-image) are used for decorative purposes — background images are not considered part of the page content and are not indexed as separate elements. They do not support alternative text and do not directly affect SEO.

Main differences:

• <img> adds an image to the document flow, affects layout, and is interactable.
• Background images via CSS do not affect the document structure and are used for styling.

Example:

<img src="logo.png" alt="Company Logo">

<div style="background-image: url('pattern.png'); width: 200px; height: 200px;"></div>

In terms of performance, <img> allows the browser to better manage loading and caching, whereas background images may be loaded only when necessary (e.g., when the element is displayed).