[Plugin: Taxonomy Images] how to get a specified term's img url?

hi,there
now,i have term_id and taxonomy,how do i get the specified term’s img url?
example:
$taxonomy = ‘market-category’;
$term = ‘computer’;
$term_id = 9;

so how to get the full-size img url ?

http://wordpress.org/extend/plugins/taxonomy-images/