Optimization Guide
Images make up the largest portion of most websites' total page weight — often 60–70% of bytes downloaded. Compressing them properly can dramatically improve page speed, SEO rankings, and user experience, all without visible quality loss.
Lossless compression reduces file size without any quality loss. It works by finding more efficient ways to encode the same pixel data — like using shorthand for repeated patterns. PNG uses lossless compression. The trade-off: file size reduction is modest, typically 10–30%.
Lossy compression achieves much greater size reduction (often 50–90%) by selectively discarding data that the human eye is unlikely to notice. JPEG and WebP use lossy compression. At quality settings above 80%, the difference is virtually invisible to most viewers.
JPEG: For photographs, 80–85% quality is the sweet spot. At 80%, file size is roughly half of 100% quality, yet the quality drop is barely perceptible. Below 70%, artifacts become visible — avoid unless file size is the absolute priority.
PNG: Use PNG only when you need transparency or sharp edges (logos, icons, screenshots of text). For photographs, converting PNG to JPEG or WebP often reduces file size by 80%+ with no meaningful quality impact.
WebP: Google's recommended format for the web. At the same visual quality, WebP files are 25–35% smaller than JPEG. For sites with many images, switching to WebP can cut image bandwidth by a third.
AVIF: The newest contender, offering even better compression than WebP (up to 50% smaller at equivalent quality). Browser support reached 95%+ in 2025. If your audience uses modern browsers, AVIF is the most efficient choice.
All processing happens in your browser. Your images are never uploaded to any server.
For developers: integrate image compression into your build pipeline. Tools like Sharp (Node.js) or ImageOptim (macOS) can batch-process thousands of images automatically. For WordPress users, plugins like Smush or Imagify handle compression on upload. For everyone else, Fluxora provides one-click compression — just drag, drop, and download.
Ready to slim down your images? Try Fluxora's Compression Tool →