Using imag_tag and Gruff

I have gotten Gruff working and I can do everything I want with it, now
the problem is serving the image from inside of a view. I can’t just
use image_tag(url_for(:controller => ‘gruff’, :action => ‘stats’))
because the html will be spit out as Stats. How do I get the image_tag helper to
supress the .png?

Thanks,
Xavier