I recently noticed that KDE creates a .diretory file to probably store info about thumbnails and other stuff and Gnome does store thumbnails in a centralised directory.

Can anyone elaborate this difference in more detail and compare the benefits and drawbacks of each approach?

Well for one I thought that KDE will save a single hidden file to every directory that has thumbnails, as compared to Gnome that has a global .thumbnails directory that stores all the thumbnail files.

I'd personally like the Gnome approach better as when you need to delete the thumbnail files you can just delete one directory an you're done. I also wonder ,if KDE creates only .directory files does it recreate thumbnails every time I enter a directory or does it have a similar global directory like Gnome?

I realised that Doplhin creates a .directory file, I'm just surprised that Nautilus does not create any file. Was wondering how does Nautilus know which thumbnails are created and which aren't and how does it know the preference for each directory (where and how does it store it's thumbnail setting database).