RE: http://goodies.xfce.org/projects/thunar-plugins/thunar-thumbnailers

I wish to have in icon preview mode, all the html or text (txt, md) previewed as thumbnails.

Some implementions, see:
* https://askubuntu.com/questions/558846/generate-thumbnails-for-text
* https://askubuntu.com/questions/381599/how-to-view-html-files-thumbnail-preview-in-nautilus
* https://stackoverflow.com/questions/15772299/generate-thumbnail-for-text-file
* http://php.net/manual/en/function.imagettftext.php
* https://stackoverflow.com/questions/65250/convert-a-doc-or-pdf-to-an-image-and-display-a-thumbnail-in-ruby
* http://www.text2image.com/

There is wkhtmltoimage, a lengthy process would be to render a temporary pdf with wkhtmltopdf

Thanks