- Server: resize uploads to max 1200px + generate 600px _thumb.jpg - Server: cache /uploads with max-age=1y immutable headers - Client: CatCard uses _thumb.jpg in feed (fallback to full on error) - Client: first 3 feed cards load eagerly (LCP), rest lazy + decoding=async - Client: loading placeholder bg while image fetches - Migration: server/src/scripts/gen-thumbs.ts for existing images Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>