Alt text (alternative text) is the attribute that describes an image in HTML. It serves three purposes: accessibility (screen readers use alt text to describe the image to visually impaired users), SEO (it helps Google understand the image's content) and fallback (it appears when the image fails to load).
Alt text best practices:
- Be descriptive and specific: "Chart showing 300% organic traffic growth in 6 months" is better than "chart".
- Include the keyword when natural: if the image is relevant to the keyword, include it. But do not force it.
- Do not start with "Image of": screen readers already know it is an image. Go straight to the content.
- Keep it concise: 125 characters or fewer. Overly long descriptions get truncated.
Beyond alt text, the image file name also matters. "link-building-strategy-2026.webp" is better than "IMG_2847.jpg" for search engines and AIs that analyze the image's context.