Fetch and ACF image field from a custom taxonomy outside category/archive page? [closed]

For fields associated with taxonomy terms, you must specify the term taxonomy along with the term id. In your case, the following would work:

$term = 'product-category_'.$range->term_taxonomy_id;
$image = get_field('range_image', $term);

Documentation: http://www.advancedcustomfields.com/resources/get-values-from-a-taxonomy-term/