All of these devices lack the large displays needed to show off the fancy graphics and complicated layouts on today's sites. By making your site navigable without graphics, you benefit sighted and blind customers alike. Most of them rely on screen reader software. Screen readers use voice synthesis to read aloud the contents of windows, menus, and other interface elements. Screen readers help visually impaired users navigate a site by interpreting HTML tags, particularly those dealing with hyperlinks, Web forms, and graphics.
Blind users can then press the tab key to jump from one link to the next.
Indeed, sighted users won't even notice most accessibility tricks. It's no news flash that graphics dominate today's sites. You can tell screen readers to ignore these file names and provide valuable context for your graphics. Concise, meaningful alt text is one of the most important accessibility features you can add. It will also improve your site for the many sighted Web users who speed up surfing by setting their browsers to skip images.