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How to Write Meaningful Image Alt Text

Good alt text does not describe every visible detail. It communicates the information users need in the page context.

Summary

  • First decide whether the image is decorative, informative, actionable, product-related, chart-like, or text-as-image.
  • Alt text should cover what users would miss if they cannot see the image.
  • AI can draft suggestions, but humans still need to confirm context, accuracy, and tone.

Start with purpose, not visual description

The same image may need different text in different contexts. A decorative brand image may not need to be announced; a product image may need style, color, or state; a chart may need trend and key values.

Common patterns

Use these categories to decide the direction quickly.

  • Decorative images: usually use empty alt text to avoid noise.
  • Informative images: provide the necessary information the image carries.
  • Images inside links or buttons: describe the action purpose.
  • Product images: describe appearance, state, or differences that affect choice.
  • Charts: summarize the conclusion and provide nearby data or full text when needed.

What to check when using AI suggestions

DevCheck can help generate image alternative-text suggestions, but AI does not fully know the image’s role on your page. Before using a suggestion, check whether it captures the point, over-describes, misses the action purpose, or uses the wrong tone.

Do not turn alt text into a fixed formula

Alt text does not have one correct length or format for every image. A more reliable question is: if users cannot see the image, what information needed for the task would they lose? If the answer is nothing, the image may be decorative. If the answer is product difference, action purpose, chart conclusion, or important text, the alt text should fill that gap.

Next checks in this workflow

This guide is part of the DevCheck pre-release checking path. After this check, continue with the next tasks below.

  1. Review color, states, and readability

    Color contrast checks before release

    Check real states such as text, focus, errors, hover, disabled controls, icons, and component boundaries.

  2. If PDFs are in scope, inspect structure signals

    PDF accessibility structure checks

    Review language, tags, images, links, forms, bookmarks, and page consistency signals.

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