Why turn a AVIF into a JPG
AVIF is new enough that plenty of software refuses it, and a picture saved from a modern website is increasingly this format. JPG is the opposite: nothing refuses it. This is the conversion that makes a file usable again.
Convert AVIF to JPG
Open an AVIF in something that has never heard of it.
This file stays on your device
Drop files here
Up to 30.0 MB
Lower makes a smaller file.
What the change costs
The file grows, often to twice the size or more, and a transparent background becomes solid black. The visible detail is kept.
When to do something else
Keep the AVIF if you are also publishing the picture. It is the better file to serve, and the JPG is only the copy that travels.