What does it do?
It converts images to WebP, AVIF (if your browser can encode it), JPEG or PNG, with adjustable quality and an optional maximum width, and shows the new size next to the original so you can see how much you save.
Why it matters
Images are usually the heaviest part of a page. Serving WebP or AVIF instead of JPEG and PNG often halves their weight, which improves Largest Contentful Paint and saves mobile data.
Tips
- Resize before compressing: a 4000px photo shown at 800px wastes most of its bytes.
- Keep PNG for images that need exact pixels, such as diagrams with fine lines.
- Transparent images become a white background when converted to JPEG.
Frequently asked questions
›WebP or AVIF?
AVIF usually compresses 20–30% more than WebP at the same quality, but encodes more slowly and is not available in every browser's encoder. WebP is supported everywhere today and is a safe default for photos and screenshots.
›What quality should I use?
Between 70 and 85 is a good range for photos: the difference is hard to see and the file is much smaller. For screenshots with text, try 85–90 or PNG.
›Are my images uploaded?
No. Decoding and encoding happen in your browser with the canvas API, so private photos never leave your device.