Why image size matters
Images often represent the largest share of bytes on a page. Reducing file size can improve load times, particularly on slower mobile connections.
Choose the right format
Use JPEG for photographs, PNG when transparency or lossless precision is essential, and WebP for broad modern-browser support. Compare output visually before replacing originals.
Choose a sensible quality level
For photographic JPEG and WebP images, begin around 75–85 percent quality, then inspect fine details and gradients. The ideal value depends on the source.
Resize before compressing
Do not ship a 4000-pixel-wide image to a 400-pixel-wide card. Generate appropriately sized images and use responsive image markup.
Measure the impact
Test with PageSpeed Insights and inspect Largest Contentful Paint. Compression helps, but caching, dimensions, lazy loading and network delivery also matter.
Further reading
Put the idea to work.
Explore free browser tools for images, text and developer workflows.