Large images slow down your website and hurt your SEO. Learn the best formats, settings, and free tools to compress images without visible quality loss.
A 5 MB hero image can make a landing page feel sluggish even on fast connections. Google's Core Web Vitals penalise slow Largest Contentful Paint scores — and large images are the single most common cause. The good news: you can cut file sizes by 60–80% without any visible quality loss, free, with nothing to install.
Every byte the browser downloads delays rendering. Images are typically the heaviest assets on a page, often accounting for 50–80% of total page weight. Studies from Google and Cloudflare consistently show that pages loading in under 2 seconds have significantly higher conversion rates and lower bounce rates.
Beyond user experience, Google uses page speed as a ranking signal. Passing Core Web Vitals — particularly LCP (Largest Contentful Paint) and CLS (Cumulative Layout Shift) — is increasingly important for SEO.
Before compressing, picking the right format does half the work:
Most image compressors expose a “quality” slider from 1–100. Here are practical starting points:
Always use your compressor's before/after preview to judge quality — numbers alone are unreliable.
If you also need to change the format (e.g. convert PNG to WebP), use the Image Format Converter immediately after compressing.
Each platform recompresses uploaded images. Pre-compress to the recommended dimensions first — Instagram uses 1080×1080px for square posts, Twitter/X uses 1600×900px for link previews. Export as JPEG at quality 80.
Export at maximum display width (typically 1440–1920px) in WebP at quality 80. Add a low-quality placeholder (LQIP) or set loading="lazy" on off-screen images using the HTML img attribute or Next.js's Image component.
Use Image Resizer & Cropper to standardise dimensions first (e.g. 600×600px), then compress to WebP at quality 78. Consistent dimensions prevent layout shifts (CLS).
| Use case | Recommended format | Quality | Expected saving |
|---|---|---|---|
| Hero / banner image | WebP | 80–85 | 40–60% |
| Product photo | WebP or JPEG | 78–82 | 45–65% |
| Thumbnail / card image | WebP | 72–78 | 55–70% |
| Logo / icon (colour) | PNG or SVG | Lossless | 20–40% (PNG) |
| Background texture | WebP or JPEG | 60–70 | 65–80% |
| Screenshot with text | PNG | Lossless | 15–35% |
Compressing images is one of the highest-ROI performance optimisations you can make. Pick WebP as your default format, target quality 78–82 for most images, and use a browser-based tool like ToolsGravity to keep your files private. Your users — and Google — will notice the difference.