Wider support, without going backwards
Every current browser and most modern software reads WebP, while AVIF support outside the browser is still patchy.
WebP is supported nearly everywhere AVIF is not. It keeps transparent areas, stays far smaller than PNG, and needs no plugin to open.
Choose the right format
This is the middle ground: a modern format with years of support behind it, at the cost of a little compression efficiency.
Every current browser and most modern software reads WebP, while AVIF support outside the browser is still patchy.
WebP stores an alpha channel, so transparent and semi-transparent areas survive the conversion.
The new file is written from the decoded pixels, so EXIF, XMP, and any location data stored in the AVIF are not carried across.
Conversion questions
Usually not. AVIF generally compresses better at the same visual quality. You trade a little file size for software that can actually open the result.
Slightly, because this is a lossy re-encode. Use the quality control to balance size against detail; somewhere around 85 to 90 is a sensible starting point.
No. Browsers can read AVIF but cannot write it, so these conversions only run one way.
No. The file is decoded, converted, previewed, and downloaded entirely inside your browser.