Why Next.js images got expensive on Cloudflare: route them through /cdn-cgi/image and cache them
Meathill explains why the default /_next/image endpoint on OpenNext was uncacheable and rerun on every request, and replaces it with a custom loader to Cloudflare Image Transformations plus a long Cache Rule.
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- Meathill (@meathill1)
Key points
- The author found /_next/image responses carried no Cache-Control, cf-cache-status, ETag or Last-Modified, so browsers and the CDN kept re-requesting and every image hit the Worker. Overriding it with Cache Rules did not take effect.
- Fix from the OpenNext docs: an image-loader.ts custom loader that emits /cdn-cgi/image/<options>/<src>, set as loader: "custom" in next.config. Responses then show unique_transformations_billing: true and respect Cache Rules.
- He then adds a Cache Rule forcing one-year edge and browser TTL on the image path, notes that LRU eviction can still drop cold images from edge caches, and suggests Cache Reserve if no re-transformation can be tolerated.
- Official docs (rechecked 2026-10-14): Images bills unique transformations once per calendar month; Free includes 5,000 and then returns error 9422 for new ones without charging; Paid includes 5,000, then $0.50 per 1,000. Cache Reserve needs a paid plan and bills storage plus Class A/B operations.
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Why Next.js images got expensive on Cloudflare: route them through /cdn-cgi/image and cache them
Open original sourceMeathill explains why the default /_next/image endpoint on OpenNext was uncacheable and rerun on every request, and replaces it with a custom loader to Cloudflare Image Transformations plus a long Cache Rule.
The author shares the image-cost article on 𝕏.
Read on 𝕏Meathill
@meathill1 · Original 𝕏 post
Next.js <Image> 很好用，但在 Cloudflare Worker + OpenNext，默认图片优化可能悄悄变成“钱包黑洞”。 我帮朋友排查了一次每月近 $100 的账单，最后发现问题藏在 HTTP Header 里。 这篇文章记录了完整排查过程，以及如何用 Cloudflare 原生 Image Resizing + custom loader + 缓存规则，把成本优化下来，把性能提升上去。 https://t.co/3ULkkPFYl0
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