The alt tag is part of the HTML standard and is also called the alt attribute. These attributes can be used to determine the alternative text for images or graphics that are displayed on a website. The alternative text describes exactly what is shown in the images.
This is useful for various purposes. So e.g. B. Images are accessible to visually impaired people because screen readers can read the image's information through the alt tag. This improves the usability of the website.
Web browsers also use the alt attributes if they cannot interpret the images or graphics. Alt tags are important for SEO because search engines cannot capture image files as such. However, the crawler can use the alternative text of the images and thus interpret the page for the image search on Google and Co. and thus rank better. For good on-page optimization, it is therefore very important to provide images with alternative texts.