Thumbnail spec in git

[Trans]

I know this is a bit far from the field, so to speak, but I've often
found it annoying that if you move a directory the thumbnails are lost
and have to be regenerated. Obviously there is nothing that can be
done about this with a shared thumbnail directory.

An ideal solution would have to be something like a directory that
"shadows" every file. This directory could hold a files thumbnails, as
well as other related information useful to different applications. It
would be a very flexible system and would totally solve the problem
--and then some. But I expect this would have to be a pretty low-level
file system thing to make sure the shadow directory is always present
and always goes where the file goes.