An image caption is a brief text description that appears alongside an image on a webpage, usually below or next to the image.

The caption’s purpose is to provide context, explain the image’s content, and convey additional information to users.

Image captions play a role in SEO in these ways:

  1. Contextual relevance: Image captions help search engines understand the content and context of an image. By including relevant keywords in the caption, you can improve the image’s relevance to the page’s overall content.
  2. Accessibility: Image captions help make webpages more accessible to visually impaired users who rely on screen readers. When a screen reader encounters an image, it will read the caption aloud, providing context for users who cannot see the image. (Note: The screen reader will also read the image’s alt text, so it’s best to use different text for the caption.)
  3. Image indexing: While image captions may not directly impact image indexing in search results (as alt text does), they can still contribute to the overall relevance and context of an image, making it more likely to appear in image search results when combined with other factors like file name, alt text, and surrounding content.

To optimize image captions for SEO, ensure they are concise, informative, and relevant to the image and the page’s content. Use natural language and include keywords sparingly, prioritizing user experience and accessibility.

In addition to SEO benefits, captions can engage users and increase time spent on a page.

Image SEO: A Common Sense WordPress Guide
Decorative Images: How to Manage Them for SEO
Image Filename SEO: How to Name Images