The <img> Keywords tag, also referred to as the <img> ALT attribute, is used to specify ALTernate text for an image. The <img> ALT attribute is not always visible to users visiting the web page with a web browser.
The HTML IMG ALT Attribute:
- The <img> ALT attribute is required for all HTML/XHTML documents containing images
- provides keywords for an image in some search engines
- provides keywords for linking URLs in some search engines
- provides keywords for browsers that are not able to display images and for visually impaired readers who can not see images