Add image optimization Lambda for `/_next/image` requests

[aynaash]

Summary

Next.js <Image> component requests images via /_next/image?url=...&w=...&q=.... Currently these requests hit the server Lambda with no optimization. We need a dedicated image optimization Lambda.

Required Components

1. Image optimization Lambda — Node.js function with Sharp compiled for arm64
2. CloudFront behavior — Route /_next/image* to the image Lambda
3. S3 integration — Fetch source images from the assets S3 bucket

Flow

CloudFront → /_next/image?url=/photo.jpg&w=640&q=75
  → Image Lambda
    → Fetch original from S3
    → Resize with Sharp (width=640, quality=75)
    → Convert to WebP/AVIF
    → Return with Cache-Control headers

Infrastructure to Auto-Provision

• New Lambda function (<app>-image-optimizer)
• CloudFront cache behavior for /_next/image*
• IAM permissions for image Lambda to read from S3

References

• OpenNext image optimization
• Sharp npm package

Difficulty: Hard · Language: Go + JavaScript