How to Reduce Image Size for a Faster Website
Images typically account for 50–75% of a web page's total download size. Reducing image weight is the single highest-impact optimisation for page speed — more impactful than minifying CSS/JS, enabling caching, or switching servers. This guide gives you a complete image optimisation workflow from upload to delivery.
Quick Answer
Images typically account for 50–75% of a web page's total download size. Reducing image weight is the single highest-impact optimisation for page speed — more impactful than minifying CSS/JS, enabling caching, or switching servers.
Try it now — free, no signup
Your images stay on your device. Nothing is uploaded to any server.
Step-by-Step Guide
5 steps · takes under 1 minute
Audit your current image weight
Open Chrome DevTools → Network tab → filter by Img. Sort by Size. This shows you every image on the page and its transfer size. Look for images over 200KB on mobile or over 500KB on desktop — these are your highest-priority targets.
Resize to display dimensions
If an image displays at 800px but you're serving a 3000px file, you're sending 14× more pixels than needed. Resize every image to its maximum display width (or 2× for retina), using the Resize tool.
Convert to WebP
Replace JPG and PNG with WebP across your site. WebP is 25–35% smaller than JPG and 26% smaller than PNG at equivalent quality. All modern browsers support it. This one change reduces image weight by roughly 30%.
Compress at 80–85% quality
After resizing and format conversion, compress at 80–85% quality. Most web images at 800–1200px wide hit 50–200KB at this setting — well within the Google PageSpeed recommended range.
Enable lazy loading for below-fold images
Add loading='lazy' to every <img> tag that's not in the initial viewport. This defers loading until the image is about to scroll into view, reducing initial page weight by 30–60% on long pages.
100% Private — Zero Uploads
ImgToolkit runs entirely in your browser using the Canvas API. Your images are never sent to a server, never stored in the cloud, and never seen by anyone else. This makes it safe for sensitive documents, client work, medical imagery, and confidential screenshots.
Pro tip
Use 75–85% quality for web images — you get 60–80% smaller files with no visible difference at normal screen sizes.
Format & File Size Comparison
Same 1080×1080px photo processed four ways
| Format | Quality | File Size | Notes |
|---|---|---|---|
| PNG (original) | Perfect | 4.2 MB | No compression — too large for web |
| Compressed PNG | Visually identical | 1.1 MB | −74% — transparency preserved |
| JPG (85% quality) | Excellent | 310 KB | −93% · Best for photos |
| WebP (85%)BEST | Excellent | 205 KB | −95% · Recommended for web |
Based on a 1080×1080px photo. Results vary by image content and complexity.
Related Free Tools
All tools run in your browser — no account or upload needed
Frequently Asked Questions
4 questions answered
Ready to get started?
Free, instant — your files stay on your device. Always.
Optimise Website Images