Use EXIF or XMP for screenshot metadata

[jonnyawsom3]

Currently metadata is stored as raw text inside a PNG chunk. This means external programs either ignore it or can't read the text. Even exiftool refuses to export the data because it's not a recognised type.

This is especially annoying when trying to convert screenshots into a newer format. I've managed to halve the size of my screenshots losslessly, but the text chunk is always ignored making it useless...

Storing the metadata inside an EXIF chunk instead would mean more programs can read it, and the metadata would be preserved when converting to newer file formats too.

Alternatively, turning the text chunk into an XMP chunk is also an option. Then you can store the metadata in custom fields rather than filling up EXIF's description tag.

Ideally there'd be a button in the screenshot manager section to convert older files to the new format too