WCAG 1.1.1: Non-text Content

Level: A. Every non-text element that conveys meaning must have a text alternative that serves the equivalent purpose. That covers images, icons, charts, image buttons, CAPTCHAs, and audio and video. Purely decorative content should be hidden from assistive technology instead.

The words "equivalent purpose" do the work. A product photo needs a description of the product. A magnifying-glass icon on a search button needs the word "Search", not "magnifying glass". A chart needs the conclusion the chart shows, which usually belongs in nearby text rather than squeezed into an alt.

• Informative images with no alt attribute, or with unhelpful alt like a filename.
• Icon-only buttons and links (search, cart, social icons) with no accessible name.
• Charts and infographics with no text summary of the data.
• CAPTCHAs with no accessible alternative.
• Decorative images that are not hidden, so screen readers announce noise.

An automated scan (free above) reliably catches missing and empty text alternatives, a large share of 1.1.1 failures. For the rest, check manually that each alternative actually conveys the right meaning. To pass: give informative images concise, purposeful alt text; name icon controls with aria-label; summarise complex graphics in text; and mark decorative images with alt="".