[taehun]

Good question. The key difference is in the transformation workflow.

Cloudflare Images requires you to pre-define "variants" in the dashboard before you can use them. Need a 800x600 crop? Go to the dashboard, create a variant, name it, then reference it in your URL like imagedelivery.net/<account_hash>/<image_id>/my-variant. Every time you need a new size or quality combination, you're back in the dashboard. It's a configure → register → use flow.

img-src.io lets you specify transformations directly in the URL query string — no pre-registration needed. img-src.io/i/john/photo.webp?w=800&h=600&q=85&fit=cover just works on the first request. You can freely combine 20+ parameters (blur, sharpen, rotate, grayscale, etc.) without touching any dashboard. It's an upload → use flow.

We do offer presets (?p:thumbnail) which work similarly to Cloudflare's variants — named parameter sets you can reuse across URLs. The difference is that presets are optional and managed via API, not a prerequisite. You can go ad-hoc when prototyping and introduce presets later when your transformation needs stabilize, rather than being forced to define every combination upfront in a dashboard.

[eduardogarza]

Cloudflare Images dot not require you to pre-define variants ... That's incorrect. I have multiple sites using it in production where I generate any size variant on the fly. It works exactly the same as you're stating that yours does.

https://developers.cloudflare.com/images/transform-images

[taehun]

You're right, and I apologize for the inaccurate information. Cloudflare Images does support on-the-fly transformations via URL parameters.

In fact, img-src.io's infrastructure runs on Cloudflare, and I initially considered wrapping Cloudflare Images for the transformation layer. However, the cost of scaling became prohibitive—if 100k free-tier users each transform 1k images, I'd be bankrupt. So I built a custom transformation service using libvips (which Cloudflare Images itself uses under the hood) and deployed it on Cloudflare Containers.

You can see the architecture here: https://docs.img-src.io/introduction#how-it-works

To be clear, this service isn't targeting folks like yourself who can spin up image transformation infrastructure in their sleep. It's for developers who find infrastructure setup tedious or daunting and just want simple image transformation with CDN caching out of the box.

Thanks for the feedback