Provide descriptive alt text for all informative images and empty alt (alt='') for decorative images.
ContextWCAG 1.1.1 (Level A). Alt text should convey the same information or purpose as the image to someone who cannot see it. For informational images, describe the content specifically: 'Bar chart showing Q3 revenue increasing 23% year-over-year' conveys far more than 'chart.' For functional images used as buttons, describe the action: 'Submit form' for a submit icon. For linked images, describe the destination: 'Visit our Facebook page.' For decorative images — spacers, visual flourishes, background textures — use empty alt text (alt='') so screen readers skip the element entirely. For complex images like charts or diagrams, consider linking to a longer text alternative via aria-describedby or a visible caption below the image. Common anti-patterns: alt text saying 'image of' or 'photo of' (redundant — screen readers already announce element type), filename-based alt text like 'hero_banner_v2.jpg', and keyword-stuffed alt text written for SEO rather than user comprehension.

