An image sitemap is an XML sitemap, or an extension added to an existing one, that lists the images on each page so search engines can find them. It is most useful when images would not otherwise be discovered by crawling the page, for example when they are loaded by JavaScript after the page opens.
How an image sitemap works
An ordinary XML sitemap lists page URLs. Google’s image extension lets each page entry also list the images that appear on that page. Inside each url entry, an image:image element wraps an image:loc element holding the image’s address. One page entry can list up to 1,000 images, and the file must declare Google’s image namespace at the top so the extra tags are understood.
There is no need for a separate file. Image entries can sit in the same sitemap as the pages, and most SEO plugins and ecommerce platforms add them automatically. Larger sites often split sitemaps by type and group them under a sitemap index.
In 2022 Google stopped using several optional image tags, including caption, title, geographic location and licence. At the time of writing (October 2026) only the image location is used, so older guides that tell you to fill in captions in the sitemap are out of date. Descriptions belong on the page, in alt text and captions, where both visitors and Google can read them.
The image URL can be on a different domain from the page, such as a content delivery network, as long as Google is allowed to crawl it.
Why it matters
For most small sites, Google finds images by crawling the pages, and an image sitemap adds little. It earns its place in particular situations: product galleries that load extra photos with JavaScript, sites with large image libraries such as photographers and estate agents, and online shops with thousands of products. For a UK retailer with several photos per product, listing all of them makes it more likely that the alternative angles are indexed, not just the first image.
Being listed does not guarantee indexing. The sitemap helps discovery; whether an image appears and ranks still depends on image SEO signals and the quality of the page it sits on.
Common mistakes
- Listing images that robots.txt blocks, so Google is told about files it cannot fetch.
- Including image URLs that redirect or return errors after a redesign or CDN change.
- Listing images on pages that are noindexed or missing from the sitemap themselves.
- Spending time on caption and title tags Google no longer reads.
- Generating two image sitemaps from two plugins, with different URL formats for the same images.
How to act on it
Check what your platform already produces. Open your sitemap in a browser and look for image entries under each page. WordPress SEO plugins and Shopify generally include images automatically. If yours does not, and your images load through JavaScript or there are a great many of them, add image entries.
Submit the sitemap, or the sitemap index that contains it, in Google Search Console, then watch the Sitemaps report for errors. Spot-check a handful of image URLs from the file to confirm they load, are not blocked and match the images on the live page. After any redesign or move to a new CDN, check again, because image URLs are often the part that changes without anyone noticing. Keeping sitemaps accurate is routine within my technical SEO work.