Practical guide
Alt Text for AI-Generated Images: Describe the Purpose, Not the Prompt
Write useful alt text for informative, functional, complex, and decorative generated images without dumping prompts or irrelevant detail.
The central idea
Alt text communicates the image’s purpose in context. The generation prompt describes how an image was requested; it often includes style instructions, failed details, and irrelevant production language that does not help someone understand the page.
A repeatable workflow
Identify the image role
Decide whether the image is informative, functional, complex, decorative, or redundant with nearby text.
Write the essential meaning
Describe the information or action a sighted reader receives in this context, not every visible object.
Handle complex images
Use concise alt text plus a nearby long description, data table, caption, or explanation for diagrams and charts.
Test without the image
Read the page with images unavailable and verify that purpose, action, and information still make sense.
Worked example
A decorative purple gradient needs empty alt text. A linked example card might use “Four product-launch concepts comparing studio, lifestyle, material, and metaphor directions.” A process diagram needs a short label plus an adjacent explanation of its stages.
Review checklist
- The image role is classified
- Alt text matches the page context
- Complex information has a long alternative
- Decorative images use empty alt
Limitations
- AI-generation disclosure belongs in context, not every alt attribute
- No automatic captioner understands the full editorial purpose