I have some taxonomy terms that have an image field in them. I am trying to get the value of the image field in my templates. How can I do this? The field's name is field_header_image.

I have this so far but it does not work..

$headerimg = field_view_field('taxonomy_term', $term, 'field_header_image'); 
print render($headerimg);

I'm guessing I need something else for taxonomy_term but I'm not sure what that should be.