Imagine: a site loads in 5 seconds, LCP exceeds 4 seconds, and all images are giant 5 MB PNGs. Clients leave, search engines penalize. Familiar? The issue is often images: they are unoptimized, not adapted to screens, and served from a slow server. We solve this with Imgix — a proxy-CDN that processes images on the fly. Result: LCP drops to 1.5 seconds, and page size reduces threefold.
Originals stay in your S3 bucket; Imgix transforms them via URL parameters and delivers them through a global CDN with edge caching. No extra copies, no manual conversions.
How Imgix processes images on the fly
On request, Imgix fetches the original from S3, applies URL parameters (width, format, quality, etc.), and caches the result on the CDN. Subsequent requests hit the cache — maximum speed. All modern formats are supported: WebP, AVIF, and automatic selection via auto=format. According to Imgix documentation, the service reduces image weight by up to 60% without quality loss.
Why Imgix is better than local processing
Local processing (GD, ImageMagick, server-side libraries) loads the CPU, requires cache space, and does not scale under peak loads. Imgix eliminates this burden:
| Characteristic | Local processing | Imgix |
|---|---|---|
| Server load | High (CPU/IO) | Zero (all on CDN) |
| Automatic formats | Requires backend | Out of the box |
| Scaling | Difficult | Horizontal (CDN) |
| Setup time | Days | Hours |
| Cost at high volumes | Grows with hardware | Fixed pricing |
Imgix is 5x faster under peak loads and requires no server administration.
How Imgix helps improve Core Web Vitals
LCP, CLS, INP — all depend on images. Imgix addresses each: LCP via preload and responsive sizes, CLS via explicit width/height, INP by reducing main thread load. We configure each parameter for your content. For example, on an online clothing store project, we deployed Imgix with signed URLs to protect product images. After setting up preload for the LCP image and srcset for the rest, LCP improved from 3.2s to 1.1s, and total page weight dropped by 55%. Contact us for a similar audit.
Which image formats does Imgix support best?
Imgix supports WebP, AVIF, JPEG, PNG, GIF, and SVG. The auto=format parameter automatically delivers the most modern format the browser supports, falling back to JPEG for browsers without WebP/AVIF. This saves up to 60% in traffic compared to the original. You can also force a format with fm=webp.
S3 Source and IAM setup
# In dashboard.imgix.com: # Sources → Add Source → Amazon S3 # S3 Bucket Name: my-assets-bucket # Access Key ID + Secret Access Key (IAM user with read-only on bucket) # Subdomain: mysite.imgix.net # IAM Policy for imgix: { "Version": "2012-10-17", "Statement": [{ "Effect": "Allow", "Action": ["s3:GetObject", "s3:ListBucket"], "Resource": [ "arn:aws:s3:::my-assets-bucket", "arn:aws:s3:::my-assets-bucket/*" ] }] } Transformation parameters
- Resize:
?w=800,?w=800&h=600&fit=crop - Format and quality:
?auto=format,compress&q=75 - Smart cropping:
?fit=crop&crop=faces(face detection) - Color and effects:
?sat=-100(grayscale),?blur=20 - Watermark:
?mark=URL&markw=20
TypeScript SDK and Signed URLs
// npm install @imgix/js-core import ImgixClient from '@imgix/js-core'; const client = new ImgixClient({ domain: 'mysite.imgix.net', secureURLToken: process.env.IMGIX_SECURE_TOKEN, // For signing URLs useHTTPS: true, }); // Generate signed URL const url = client.buildURL('products/shirt-red.jpg', { w: 600, h: 600, fit: 'crop', auto: 'format,compress', q: 80, }); // srcset for responsive images const srcSet = client.buildSrcSet('products/shirt-red.jpg', { auto: 'format,compress', fit: 'max', }, { widths: [320, 480, 640, 800, 1080, 1200, 1600], }); Next.js: custom loader
// lib/imgix-loader.ts import ImgixClient from '@imgix/js-core'; const client = new ImgixClient({ domain: process.env.NEXT_PUBLIC_IMGIX_DOMAIN!, secureURLToken: process.env.IMGIX_SECURE_TOKEN, }); export default function imgixLoader({ src, width, quality, }: { src: string; width: number; quality?: number; }): string { const path = src.startsWith('http') ? new URL(src).pathname : src; return client.buildURL(path, { w: width, auto: 'format,compress', q: quality ?? 75, fit: 'max', }); } // next.config.ts const nextConfig = { images: { loader: 'custom', loaderFile: './lib/imgix-loader.ts', }, }; import Image from 'next/image'; <Image src="/products/shirt-red.jpg" alt="Red shirt - imgix optimized" width={600} height={600} sizes="(max-width: 640px) 100vw, (max-width: 1024px) 50vw, 33vw" priority={isAboveFold} /> Performance optimization
<link rel="preload" as="image" href="https://mysite.imgix.net/hero.jpg?w=1200&auto=format&q=80" imagesrcset="..." imagesizes="100vw"/> What's included in the Imgix integration work?
- Audit of current images and their impact on Core Web Vitals
- Design of S3 bucket structure and IAM policy configuration
- Imgix connection: source setup, custom subdomain, SSL
- Integration with your stack: ready code for Next.js, Vue, React, or plain HTML
- Signed URLs for private content protection
- Preload and srcset optimization for critical images
- Usage documentation and team training
- One month of post-launch support
Process and timeline
We audit your current images, design the S3 bucket structure, and connect Imgix. One engineer handles this in 1–3 business days. You get:
- Configured S3 bucket with IAM policy
- Working proxy-CDN with custom subdomain
- Ready integration code for your stack
- Signed URLs for private content
- Documentation and one month of support
5-step setup
- Create an S3 bucket and a read-only IAM user.
- Add the source in the Imgix dashboard.
- Configure transformation parameters for your content.
- Implement a custom loader for your framework.
- Check Core Web Vitals and optimize preload.
Common problems and solutions
| Problem | Solution |
|---|---|
| Slow first image load | Set up preload for LCP images |
| Incorrect aspect ratio display | Use fit=crop with focus |
| High bandwidth consumption | Enable auto=format,compress |
Get a free project assessment: we'll analyze your images and show how much faster your site can be. Over 5 years of experience, 50+ successful projects with Imgix. We guarantee a working integration and performance metric compliance. Contact us for a consultation.







