How to Compress Images for Websites — Speed Up Your Site

Why Image Optimization Matters for SEO

Google uses page speed as a ranking factor. Core Web Vitals — specifically Largest Contentful Paint (LCP) — measures how fast your main content (usually a large image) loads. A poor LCP score suppresses rankings and increases bounce rates.

Impact of unoptimized images: - A 3 MB hero image adds 3+ seconds to page load on mobile - Google penalizes pages that load in over 3 seconds - Users abandon pages after 3 seconds of waiting

Impact after optimization: - Same image at 150 KB: loads in under 0.3 seconds on most connections - LCP scores improve dramatically - User engagement increases

The Optimal Image Workflow for Websites

For every image you add to a website, follow this process:

Step 1 — Resize to actual display size: If a hero banner displays at 1440px max-width on desktop, resize to 1440px. Uploading a 4000px photo that displays at 1440px wastes 8× the bandwidth.

Step 2 — Choose the right format: - Photos → WebP (or JPEG fallback) - Illustrations, logos, screenshots → WebP or PNG - Simple icons → SVG (vector, infinitely small)

Step 3 — Compress: JPEG at 80–85% quality. WebP at 75–80% quality.

Step 4 — Use lazy loading: Add `loading="lazy"` to image HTML tags so images below the fold don't load until scrolled to.

WebP — The Best Format for Web Images

WebP is 25–35% smaller than equivalent JPEG or PNG at the same visual quality. All modern browsers support WebP (since Safari 14, 2020).

Converting to WebP with PDFBro: 1. Upload your JPEG or PNG to the Image to WebP tool 2. Set quality to 80% 3. Download WebP files

For older browser compatibility, provide both WebP and JPEG using the HTML `<picture>` element with a JPEG fallback.

• 1

  Use Google's Squoosh tool alongside PDFBro for side-by-side quality comparison when setting compression levels.

• 2

  Automate image optimization in your CMS with plugins (WordPress: Smush, ShortPixel) for images uploaded by content editors.

• 3

  Set max-width in CSS so browsers don't display images larger than their container — prevents visual quality issues regardless of upload size.

Frequently Asked Questions