About ImageGuide

ImageGuide is a free reference site for image optimization on the web. It covers the whole pipeline: choosing the right format, compressing without visible loss, resizing for every screen, and delivering images fast through a CDN. Every guide is practical, tested against real encodes, and free to read — no account, no paywall, no upsell wall.

What you will find here

• 100+ in-depth guides — formats, compression, responsive images, Core Web Vitals, image SEO, and delivery.
• Free browser tools — converters for every common format pair, a compressor, an image analyzer, and a comparison slider.
• Reference sections — recommended dimensions per platform, per-industry workflows, and per-platform guides for Shopify, WordPress, Wix, Squarespace, and Webflow.
• AI-ready access — structured llms.txt, an AI info page, markdown versions of every guide, and complete schema markup.

Who publishes it

ImageGuide is published by Sirv, an image CDN and dynamic imaging company based in Oxford, United Kingdom. Sirv handles image delivery, resizing, zoom, 360 spins, and AI-powered image editing for e-commerce sites. The guides on ImageGuide are editorially independent: where a file size or compression ratio is quoted, it comes from an encode run on a stated image set rather than from a vendor claim. Sirv products are mentioned where they are genuinely the simplest path, and never required to use the guides or tools.

How the site is built

The site is a static Astro build served from the edge. Images are delivered through Sirv's CDN with automatic format negotiation, so the pages themselves practice what the guides preach: WebP and AVIF variants, responsive widths, long-lived caching, and lazy loading below the fold.