What is the purpose of the alt attribute in an img tag?

The "alt" attribute in an <img> tag is used to provide alternative text for the image. This text will be displayed if the image cannot be loaded or if the image is being read by a screen reader. The purpose of the "alt" attribute is to provide a brief description of the image's content, so that people who are unable to view the image can still understand the context and purpose of the image.

The "alt" attribute is also important for accessibility and SEO as it helps assistive technologies to understand the contents of the image and it also helps search engines to understand the context and purpose of the image. When the search engines find that the alt tag is empty or missing, it could affect the ranking of your webpage.

It's a best practice to always include the "alt" attribute in your <img> tags and provide a meaningful and concise description of the image.