thumbnail generator grayscale

http://snippet.gabory.fr/snippet/13/

Based on the thumbnail templatetag you can found in http://mezzanine.jupo.org CMS but convert your image into grayscale. just use it like the classical thumbnail templatetag. For example :
<img
class="featured-thumb"
src="{{ MEDIAURL }}
{% bwthumbnail blogpost.featured_image 90 90 %}"