[Alternate AVIF Fix] (7.04.2023)
If you open an image full screen, inspect the image element via dev console, open the img src
you can save the image not as avif
. At least in my case. Allowed me to save as PNG this way.
To "Inspect" the page to get the file: Right Click on the Page and you should see a dropdown menu "Inspect Element" click on that and you should see a pop up happen on the page you are on:

Viola! all the file should have all the prompts (If it has it) on the image you saved.
Just make sure to ctrl + s
instead of using the right mouse click and then save method. You're welcome, found this on Discord and I thought I'd share it :)
GhostBell,
Your Local Internet Hobbit