Alt Text for Images
Alt tags provide text to describe images on your web page. When a user of screen reader technology encounters an image, the alt text is what they will hear so it is important to provide an alt tag for all images. Make sure to convey any meaning in the alt tag that the picture would provide for a sighted user. Also avoid redundant wording such as “Picture of” or "Image of” in your alt tags as the screen reader technology will handle that for you.
If the image contains text, include that in the alt attribute so the screen reader technology can access and convey it.
For images that are purely decorative and add no additional information to your web page, use a null alt tag like this: alt=” “. This will tell the screen reader to skip the image entirely.
If your image is a link, do not describe the image but instead use the alt text to describe what will happen when the user clicks the link.