What AVIF is
AVIF is a modern image format based on the AV1 video codec. It makes very small files with good quality, so many websites and some Android phones now use it. But many photo editors, printers, Windows programs and upload forms still cannot open AVIF files.
What happens when you convert
The AVIF picture is decoded by your own browser and saved as a JPG. Transparent areas become white, because JPG has no transparency. Choose the quality (40–100, default 92) and, if you want, a smaller width in pixels; pictures are never enlarged. Several files can be converted at once.
Browser support
Recent versions of Chrome, Edge, Firefox, Opera and Safari can decode AVIF. If your browser is old, the file will not open — update the browser and try again.
Common problems and how to fix them
“Could not be opened as an image”: your browser cannot decode this AVIF, or the file is damaged. The JPG is much bigger than the AVIF: that is normal because AVIF compresses better; lower the quality to 80–85. You need transparency: use Image to PNG instead.
Good habits
Keep AVIF files for websites where they save data, convert copies to JPG for sharing and printing, and check one converted picture at full size before converting many.