Why it matters to a buyer
Alt text is one of the few places accessibility and search overlap directly: the same short line lets a screen reader user know what an image shows and lets an image rank in Google Images or be understood by an assistant that cannot see the page. Sites that skip it are harder to use for real customers with visual impairments and lose a source of relevant traffic. A buyer should ask whether alt text is written per image, describing what matters in that specific photo, rather than filled with a generic template line copied across a catalogue.
How it is measured or applied
Alt text is written as a short, specific sentence describing the image's content and purpose, not its file name or a list of keywords; a decorative image that adds nothing can carry an empty alt attribute so screen readers skip it. Product photos should name the product and its distinguishing detail, while a purely visual banner needs shorter, functional text. It is checked with an accessibility scanner or a crawler that flags missing or empty alt attributes, and periodically sampled by hand, since automated tools cannot judge whether a description is accurate or just present.
Sources
- Google Images best practices, Google Search Central
