Alt text: Alt (short for ‘alternative’) text is HTML code that allows text to be added to a graphic image. This text will be readable by users who have images disabled in settings, or who hover their pointer above a banner. Alt text is frequently used to add emphasis or prompt click-throughs.
Alt text is most appropriately used for people with visual impairments, people with outdated internet browsers and/or slow internet connetions and also search bots. Adding alt text to a picture can actually make that picture readable to a search bot when it crawls over the page to check content.