Why Unoptimized Media Destroys Core Web Vitals
In modern web applications, images account for over 65% of total page weight transferred across the wire. Serving bloated JPEG or PNG assets directly inflates Largest Contentful Paint (LCP) times past Google’\”s 2.5-second threshold, triggering search engine ranking demotions. In Next.js 15, combining the native next/image optimizer with modern AVIF and WebP compression formats slashes media payload weights by up to 82% with zero perceptible loss in visual fidelity.
Documented by Saizul Amin for frontend performance engineers and Core Web Vitals specialists.
Format Compression Comparison (1920×1080 Hero Graphic)
| Image Format | File Size | LCP Network Transfer Time (Fast 4G) | Bandwidth Savings |
|---|---|---|---|
| Baseline PNG | 1,420 KB | 1,850ms | Baseline (Heavy) |
| Optimized JPEG | 480 KB | 620ms | 66.2% Smaller |
| Google WebP | 210 KB | 270ms | 85.2% Smaller |
| Next-Gen AVIF | 115 KB | 140ms | 91.9% Bandwidth Reduction |
Next.js 15 next.config.ts AVIF Configuration
// next.config.ts
import type { NextConfig } from '\''next'\'';
const nextConfig: NextConfig = {
images: {
formats: ['\''image/avif'\'', '\''image/webp'\''],
minimumCacheTTL: 31536000, // 1 year immutable edge cache
deviceSizes: [640, 750, 828, 1080, 1200, 1920, 2048],
imageSizes: [16, 32, 48, 64, 96, 128, 256, 384],
},
};
export default nextConfig;
Saizul Amin is a digital growth strategist and SEO consultant specialising in search engine optimisation, web development, AI-powered automation, and online income systems. With 8 years of hands-on experience helping businesses and individual creators grow their online presence, Saizul combines technical expertise with practical, results-driven strategy.
Experience & Background
Saizul started his digital career in 2017, initially working with Bioscope Limited to build and optimise websites for organic search traffic. Over the years, he has worked across industries including DGHS, NAVANA, UNICampus, UNIPathways, UniqueMark, developing a deep understanding of what it takes to rank, convert, and grow sustainably online.
His work spans the full digital stack — from technical SEO audits and content strategy to WordPress development, marketing automation, and AI tool integration for small businesses and startups.
What He Covers on This Blog
Every article on SaizulAmin.com is written from direct experience. Saizul does not publish theoretical content — every guide, tool recommendation, and strategy shared here has been tested and applied in real projects. Topics include:
- Search engine optimisation (on-page, technical, and content SEO)
- Digital marketing strategy and growth systems
- AI tools and automation for business productivity
- Web development, WordPress, and website building
- Making money online through freelancing and affiliate marketing
Why Trust This Content
All recommendations on this site reflect tools and strategies Saizul actively uses or has personally evaluated. Where affiliate relationships exist, they are clearly disclosed. Content is regularly reviewed and updated to reflect current best practices and algorithm changes.