Target image sizes for web performance
Google's Core Web Vitals measure Largest Contentful Paint (LCP) — how fast the main image on your page loads. A 2MB hero image is the most common reason sites fail LCP. Compressing it to under 200KB can cut load time by 60–80% with no visible quality difference on screen.
| Image Type | Target Size | Recommended Quality | Format | Pre-configure |
|---|---|---|---|---|
| Hero / banner image | Under 200KB | 80% | JPEG or WebP | Open ↗ |
| Blog post images | Under 150KB | 80% | JPEG | Open ↗ |
| Product images (Shopify) | Under 100KB | 85% | JPEG | 100KB Tool ↗ |
| Logo / icon (with transparency) | Under 50KB | — | PNG | PNG Tool ↗ |
| Background textures | Under 100KB | 75% | JPEG or WebP | Open ↗ |
| Thumbnail / card images | Under 50KB | 80% | JPEG | 50KB Tool ↗ |
How slow images hurt your Google rankings
Since May 2021, Google includes Core Web Vitals (CWV) as a direct ranking factor. The key metric for images is Largest Contentful Paint (LCP) — how long it takes for the main image on a page to load. Google's threshold: good = under 2.5 seconds, poor = over 4 seconds. A 2MB hero image on a mobile connection can take 6–10 seconds — automatic "poor" rating and a ranking penalty.
Every 100KB you remove from your images is roughly 0.2–0.4 seconds off LCP on a mobile connection. Compressing a 2MB banner to 200KB can move a "poor" LCP score to "good" — directly improving your search ranking without any other changes.
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Step-by-step: compress images for WordPress (3 steps)
Upload your image here. The tool is pre-set to 150KB at 80% JPEG quality — the web optimisation sweet spot. Adjust target to 200KB for hero images or 50KB for thumbnails.
Click Compress and review the before/after preview. At 80%, photos look identical on screen. If you see visible quality loss, nudge quality up to 85%.
Download and upload to WordPress/Shopify/Wix. In WordPress, always add descriptive alt text after uploading — this is a separate but equally important SEO step that Google uses for image ranking.
Frequently Asked Questions
Should I use JPEG or WebP for my website images?
WebP is 25–35% smaller than JPEG at the same quality and is now supported by all modern browsers (Chrome, Firefox, Safari, Edge). If your CMS supports WebP (WordPress 5.8+, Shopify, and most modern builders do), use WebP. If you need maximum compatibility with older browsers or email, use JPEG. This tool outputs both — just select your format before compressing.
Do I still need an image optimisation plugin if I use this tool?
This tool handles manual compression before upload. WordPress plugins like Imagify or Smush re-compress images that are already on your server. If you pre-compress properly with this tool, you need less aggressive plugin compression — which means better quality. Many developers pre-compress with a tool like this and use a plugin only for automated resize on upload (different srcset sizes for responsive images).
What's the maximum image size I can upload to WordPress?
WordPress's default max upload size is set by your hosting's php.ini — typically 2MB to 64MB. But the real question is what size you should upload: under 200KB for any image that appears on a page. Larger images are fine as downloads, but images that load on a webpage should be compressed first.