Image sitemaps: what they do

Why it works

A regular sitemap lists pages a crawler should index. An image sitemap lists images individually, inside the sitemap, using a second namespace. It tells the engine where each image lives and which page it belongs to. The engine can still discover images by crawling the page HTML, but an image sitemap is a direct pointer that helps pages where images are hard to reach: lazy-loaded galleries, lightboxed overlays, or images only injected from scripts.

It is a supplementary signal, not magic. On-page alt text and context from the image SEO guide still do the ranking; the sitemap does the discovery. Use it where you have a large, structured image set: e-commerce product photos, galleries, media pages.

The XML structure

The file is a normal sitemap with an extra namespace declaration, xmlns:image="http://www.google.com/schemas/sitemap-image/1.1", and <image:image> blocks inside each <url>:

<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"
        xmlns:image="http://www.google.com/schemas/sitemap-image/1.1">
  <url>
    <loc>https://example.com/products/coastal-hoodie</loc>
    <image:image>
      <image:loc>https://example.com/media/coastal-hoodie-front.webp</image:loc>
    </image:image>
    <image:image>
      <image:loc>https://example.com/media/coastal-hoodie-detail.webp</image:loc>
    </image:image>
  </url>
</urlset>

Rules for the values:

• <image:loc> is the only field that matters today. The companion tags image:title and image:caption were deprecated by Google and are ignored, so leave them out of new sitemaps. The legacy image:geo_location and image:license fields still parse if you have that data, but they are no longer required or rewarded.
• <image:loc> must be an absolute URL and reachable without a login.
• Prefer the canonical site domain for image URLs. Google does allow cross-domain or CDN image hosting, but only when both hosts are verified in Search Console.
• One <url> can hold many <image:image> blocks, up to 1000 images per page in Google's guidance.
• Place <loc> before the <image:image> blocks.

When it pays

• Galleries and portfolios where the images are lazy-loaded via script and the page HTML does not carry all src values.
• Product catalogue pages where each item has multiple photos.
• Sites where geographical or editorial coverage is driven by photos (a newsroom).

It costs little and occasionally rescues discovery. Where the site already exposes all images in static HTML, the benefit is smaller.

Submitting and referencing

1. Create sitemap-images.xml in the server root.
2. Reference the regular page sitemap, the image sitemap, or both in robots.txt:

Sitemap: https://example.com/sitemap-images.xml

1. In Google Search Console, submit the sitemap URL under Indexing and watch the Image coverage line.

Common validation errors

The report tool shows the errors:

Re-submit after large changes. The full picture of image search signals is in the image SEO guide. Serve the images the sitemap points to from a cached CDN with stable URLs, which the image optimisation guide covers under delivery.