Hello,

I am author of github.com/novomesk/qt-avif-image-plugin

AVIF is a new image format based on AV1 compression. Firefox has support for AVIF (but disabled by default), Google is working to add support into Chrome.

Even before Firefox, Konqueror was able to display AVIF in websites after following trivial patch in khtml:
www.reddit.com/r/AV1/comments/faayy9/avif_image_browser_test/

I propose following changes in src/imload/decoders/qimageioloader.cpp:

1)
In bool isSupportedFormat(QString format)
Check if AVIF is listed in QImageWriter::supportedImageFormats()
and mark AVIF as supported (return true).

2)
In bool imageFormat(QImage &image, ImageFormat &format)
in default switch case - instead assuming "unsupported formats", what about converting them to supported?

if ( image.hasAlphaChannel() ) {
  image = image.convertToFormat( QImage::Format_ARGB32 );
  format.type  = ImageFormat::Image_ARGB_32_DontPremult;
}
else {
  image = image.convertToFormat( QImage::Format_RGB32 );
  format.type  = ImageFormat::Image_RGB_32;
}

AVIF test files here:
github.com/AOMediaCodec/av1-avif/tree/master/testFiles