I just discovered that there's a programm called
calibre2opds with documentation in our wiki that does basically the same and much much more! Displaying covers, showing the description, browsing books by author, date,...
Thank you for pointing that out Sischa!
Well, maybe the method above is a valid option if you want to have a better performance on your Kindlebrowser in your library than with calibre2opds' access. Or if you prefer the lean Pyndexer directory over the lush calibre2opds access and a simpler setup. And of course for Kindle owner without Calibre, who want to access their library over whispernet.