Matthias Clasen authored Sep 22, 2022 and Marco Trevisan committed Dec 08, 2022

Some applications (eg., gnome-photos) really want a large thumbnail,
if one can be created. Simply falling back to a smaller one (probably
created by an old nautilus), without giving the application a chance
to create a bigger thumbnail, is undesirable because they will appear
fuzzy.

Therefore, at separate attribute sets for all the thumbnail sizes
that are supported in the spec: normal/large/x-large/xx-large.

The old attribute will now return by default the biggest available, as
it used to be, but also including the x-large and xx-large cases.

Co-Authored-by: Marco Trevisan <mail@3v1n0.net>

Fixes: #621