Image sitemaps
Image sitemap information uses Google's image sitemap extension to list images associated with a page, helping Google discover images it might not otherwise find — for example those loaded via JavaScript or referenced in CSS. This page covers the image namespace, the per-page image limit, and when image sitemap data is worth adding.
What this means
An image sitemap is a standard XML sitemap that adds Google's image namespace so each url entry can list one or more image:image children with an image:loc (the image URL). It helps Google find images associated with the page.
This is most useful when images are not easily discoverable from the HTML — for instance images loaded by JavaScript or referenced only in CSS background properties — which normal crawling may miss.
Format and limits
Add the image namespace to the sitemap's urlset, then under each url, include image:image entries with image:loc. You can list up to 1,000 images per page in the sitemap. Image URLs may be on a different host (such as a CDN), provided that host is verified or you use the sitemap to indicate ownership.
Google deprecated several image-specific sub-tags (like caption, title, and license), so image:loc is the key remaining field. Use absolute URLs and keep the listed images present on the page.
- Add Google's image namespace to the urlset
- Each url can list image:image children with image:loc
- Up to 1,000 images per page
- Several image sub-tags are deprecated; image:loc remains
When it helps
Image sitemap data mainly helps when images would otherwise be undiscoverable — JavaScript-injected images, CSS backgrounds, or images on a separate CDN host. For images already present as standard img elements in the HTML, Google can usually find them by crawling, so a sitemap adds little.
It is a discovery aid for Google Images, not an indexing guarantee. Validate the sitemap structure and confirm the image URLs return 200; broken image URLs simply will not be indexed.
How it appears in analytics and logs
Image sitemap entries tell Google which images belong to a page so it can crawl images it might otherwise miss. They aid image discovery for Google Images; they do not guarantee image indexing and add no benefit for images already discoverable in the HTML.
Diagnostic use case
Help Google discover images that are hard to find through normal crawling, such as JavaScript-loaded or CSS-referenced images, by listing them in a sitemap.
What WebmasterID can help detect
WebmasterID shows which crawlers fetch your pages and image URLs and the responses returned, helping confirm that image assets you list are reachable and return 200 to crawlers rather than erroring.
Common mistakes
- Adding image sitemap entries for images already discoverable in plain HTML img tags.
- Listing image URLs that 404 or are blocked, so they cannot be indexed.
- Relying on deprecated image sub-tags instead of image:loc.
- Expecting an image sitemap to guarantee image indexing.
Privacy and accuracy notes
Image sitemaps reference public image URLs and the pages that host them, not visitors. WebmasterID records crawler fetches as bot events and stores no user data.
Frequently asked questions
- When should I use an image sitemap?
- When images are hard to discover through normal crawling — for example JavaScript-loaded images, CSS background images, or images served from a separate host. For standard HTML img elements, Google can usually find them without a sitemap.
- How many images can I list per page?
- Up to 1,000 images per page in the sitemap, each with an image:loc. Several older image sub-tags have been deprecated, so image:loc is the main field to provide.
Related pages
- XML sitemap best practices
An XML sitemap lists URLs you want crawled, helping search engines discover pages they might miss through links alone. The format has firm limits — 50,000 URLs and 50MB uncompressed per file — and works best when it contains only canonical, indexable, 200-status URLs with accurate lastmod values. This page covers the documented rules and the common quality problems that make a sitemap less useful.
- Video sitemaps
Video sitemap information uses Google's video sitemap extension to describe videos on a page — title, description, thumbnail, and either a content or player URL — so Google can discover and understand them for video features. This page covers the required video namespace tags, the relationship to VideoObject structured data, and common pitfalls.
- JavaScript rendering and crawling
Content injected by JavaScript is not in the initial HTML, so a crawler must render the page to see it. Rendering is more expensive than fetching HTML, and not all crawlers render. Server-side rendering (SSR) or prerendering puts content in the HTML directly, reducing dependence on the crawler's render step.
- Website observability
Confirm crawlers can reach your image assets with a 200 response.
Sources and verification notes
- Google Search Central — Image sitemapsImage namespace, image:loc, and the 1,000-images-per-page limit.
Last reviewed 2026-06-24. Facts are checked against primary/official sources where available; uncertain specifics are marked “Data not yet verified” rather than guessed.