If you want fast-loading pages and small files, the format you pick matters a lot. Here is the short version, then the details.

The quick answer

• AVIF gives the smallest files at a given quality, often 30 to 50% smaller than JPEG. Support is now good in modern browsers but not universal.
• WebP is a bit larger than AVIF but has wider, more mature support and encodes faster. A safe default for the web.
• JPEG is the most compatible. Use it when something must open absolutely everywhere, or for compatibility fallbacks.

File size and quality

At the same visual quality, AVIF usually wins on size, WebP is in the middle, and JPEG is the largest. For photos, both AVIF and WebP keep detail better than JPEG at low file sizes (JPEG shows blocky artifacts sooner). For flat graphics and screenshots, PNG or lossless WebP may be better than any lossy format.

Transparency and animation

WebP and AVIF support transparency (alpha), JPEG does not. Both WebP and AVIF also support animation, which can replace heavy GIFs.

Browser support

WebP is supported in essentially all current browsers. AVIF is supported in current Chrome, Firefox, Safari and Edge, but older devices may not decode it. When in doubt, ship WebP, or provide a JPEG fallback.

What to do in practice

Convert your images to WebP or AVIF and keep quality around 60 to 80 for photos. You can do this privately, without uploading anything, with our image compressor or the dedicated PNG to WebP and JPG to WebP converters. To go smaller still, try PNG to AVIF. If you need maximum compatibility, convert back with WebP to JPG or AVIF to JPG.