Go live in minutes • no install • built for ecommerce & content

Ship faster pages with perfectly sized, modern images.

ReadyCMS Image Resizer is a managed image transformation and delivery service. It fetches only from domains you control, generates the exact variants your site needs (resize, crop, WebP/AVIF), caches the result, and serves repeat traffic fast—without rebuilding storage or maintaining an image pipeline.

Try the demo
  • No install / no setup
  • Works with any stack / CMS
  • Your domains only
Faster page loads
Right-size images for mobile and Core Web Vitals.
Consistent variants
One URL contract → one deterministic, cached output.
Less maintenance
No installs. No pipelines. No babysitting.
A simple URL contract
Works with any stack. No SDK required.
What happens on each request
fetch → transform → cache
Input
Your original URL
Transform
Size • fit • WebP/AVIF
Output
Cached variant
Example request
/?url=https://cdn.yourstore.com/products/sku-123.jpg&w=600&h=600&fit=cover&format=webp&compress=82

Use an allowlisted source domain you control. Responses are cached and served with ETag and immutable caching headers. Change the source URL (or version it) when the underlying image changes.

Formats
PNG, JPEG, WebP, AVIF (when enabled). TIFF via Imagick.
Guardrails
Allowlisted domains + SSRF mitigation.
Fit: cover / contain Adjustments: rotate / flip (optional) Cache: disk + immutable
Who it’s for

Best fit when you control your image domains and need consistent, repeatable variants across a CMS or ecommerce site.

Best for
  • Ecommerce: PLP/PDP grids, thumbnails, category pages
  • Content sites: heroes + inline images at scale
  • Agencies: repeatable presets across clients
  • Platform teams: guardrails + predictable delivery
Not for
  • Open resizing of arbitrary public URLs
  • DAM/workflow tools (tagging, approvals)
  • AI image editing pipelines
Ecommerce Content sites Agencies Platform teams
Positioning

What we are (and what we’re not)

Clear boundaries keep the product reliable, secure, and easy to roll out.

We are
  • A managed image transformation + delivery service
  • A URL-based image API that resizes/optimizes and caches outputs
  • A first-party image domain option (custom subdomain) when needed
  • Cache-first, deterministic outputs
  • An enterprise path (dedicated environment option)
We are not
  • A photo editor or creative tool
  • A DAM / media library / content hub
  • A generic open proxy for the public internet
  • A “do-everything” media platform

Request a demo / technical evaluation

Tell us your image domains and traffic profile. We’ll respond with a recommended configuration (allowlists, limits, caching) and a rollout plan.

Typical image types
Security / compliance needs
We typically respond within 1 business day.

Note: we may record attempted demo source domains for abuse prevention and to help with follow-up. See Privacy.

How it works

A rollout you can explain to your team

Allowlist your image domains, update your image URLs, and let caching do the heavy lifting.

1) Allowlist your domains

We only fetch from the domains you approve (exact hosts and *. wildcard subdomains).

2) Update your image URLs

Set size, fit, and format with w/h, fit, and format. No SDK—just a URL.

3) Cached for repeat traffic

Variants are stored on disk and served with ETag and immutable caching for repeat performance.

Architecture

Delivery options

Use Image Resizer as your variant generator and cache. Most teams place it behind their CDN; some teams serve variants under a first‑party subdomain.

Behind your CDN

Browser → CDN → Image Resizer → your image source

First‑party delivery

Serve variants from your own subdomain (for consistent, first‑party URLs) when required.

Want the safest rollout?

Features

Everything is built around a clear contract: one request produces one cached variant.

Layout control

Resize with layout control

Generate consistent variants with fit=cover or fit=contain, plus crop anchoring via cover-position.

Modern formats

Convert formats on demand

Output PNG, JPEG, WebP, GIF, TIFF (Imagick), and AVIF (avifenc) without changing how you store originals.

Cache-first

Caching for repeat traffic

Disk cache plus immutable HTTP caching reduces origin fetches and keeps pages fast.

Optional

Basic adjustments (not a photo editor)

When you need it: rotate, flip, and a few lightweight adjustments via query params. This is intentionally limited—Image Resizer is built for reliable delivery, not creative workflows.

Try the URL API

Use query parameters to define the output image. First request generates; repeat requests are served from cache. For production, start with one template and expand.

Base URL: https://image-resizer.readycms.io
Example
/?url=https://example.com/a.jpg&w=600&h=400&fit=cover&cover-position=top-right&format=webp&compress=85

Replace the URL with an image hosted on an allowlisted domain.

Common parameters
url
Source image URL (required)
w / h
Target width/height (px)
fit
cover (default) or contain
format
png, jpeg, webp, gif, tiff, avif
compress
JPEG/WebP quality or PNG compression

Test demo

Build a request and preview the returned image. Use the sample image, or upload/import your own for a same-origin demo.

Open in new tab

Tip: this demo is pre-filled with a hosted PNG sample image (SVG is not supported). For production, your image domains must be allowlisted. For testing, upload/import to get a hosted URL under this domain. (Uploads are temporary.)

Advanced parameters

Hex: RRGGBB or RRGGBBAA (optional alpha).

If set, it uses a safe JSON spec under textOverlay.

Preview
Paste an allowlisted image URL to load a preview.
Transformed image preview

Production base URL: https://image-resizer.readycms.io/

Demo note: we may record attempted source domains for abuse prevention and to help with follow-up. See Privacy.

FAQ

The questions that come up in real deployments.

Is this a CDN? ▾

No. ReadyCMS Image Resizer generates and caches image variants. Many teams place it behind a CDN, but it’s not positioned as a general CDN replacement.

Do we need to pre-generate variants? ▾

No. Variants are generated on demand based on the request parameters, then cached for future requests.

What happens if a source domain isn’t allowlisted? ▾

Image Resizer is designed for intentional use: it only processes images from domains you approve. If a domain isn’t allowlisted yet, contact sales and we’ll help you add the right hosts (including wildcard subdomains if needed).

Do you store our original images? ▾

No. You keep your originals where they already live. We fetch the original only to generate the requested variant, then cache the transformed output for repeat requests.

What limits should we expect? ▾

Defaults are designed to prevent abuse and keep performance predictable: source downloads are capped at 20 MiB, output dimensions are clamped to a maximum of 4000px, and very large decoded images are rejected. If you have a legitimate use case that needs different limits, talk to sales.

How do you handle transparency? ▾

PNG/WebP/AVIF outputs preserve transparency. If you output JPEG, transparency is flattened onto a background color.

Can we prevent upscaling small images? ▾

Yes. You can disable upscaling so small source images won’t be enlarged beyond their original size. This is useful to avoid blurry product thumbnails.

What happens when the source is slow or temporarily unavailable? ▾

The first request may be slower because it has to fetch and generate the variant. After that, cached variants serve quickly. If a fetch fails, the request won’t produce a new cached variant; this is why we recommend rolling out gradually and monitoring behavior.

Predictable variants. Fewer regressions.

If you control your image origins and need consistent variants, this gives you a simple contract: request a variant, get a cached optimized result.

View the URL API

ReadyCMS Image Resizer — image resizing, format conversion, and caching.

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