Case: Image sitemap recovered 22% image traffic

Case: Image sitemap recovered 22% image traffic
A recipe site had 140,000 images but no image sitemap. Google Images surfaced almost none.
What we did:
— Added <image:image> blocks under each page URL (max 1,000 images per URL)
— Listed only the hero and step images, not decorative icons
— Submitted as a separate file in the index
Measured outcome over 8 weeks:
— Images indexed: ~9,000 → 118,000
— Google Images referral sessions up 22%
Checklist:
✅ Image URLs absolute, 200-status, not blocked in robots.txt
✅ Max 1,000 <image:image> entries per page URL
✅ Decorative/UI images excluded
Definition of done: every indexable content image appears under exactly one page URL.