Alt text, short for "alternative text", is a brief text description of an image’s content that is displayed when an image is not visible on the page. It describes the content of the photo, usually explaining visual details that might otherwise be unnoticed. People using screen readers are able to hear the alt text in place of the image.
All images used on ElectionAccess.org have alt text available. Below is a screenshot that shows an example of alt-text for this photo of a Georgian voter using a mobile ballot box (shown in the gold circle):