I got it working using the Wysiwyg Editor to upload the image instead. Thanks for your help.
The final code is
add_action('woocommerce_single_product_summary','finish_image',22);
function finish_image() {
$terms = get_the_terms( $post->ID , 'pa_metal-finish' );
if($terms) {
foreach( $terms as $term ) {
echo '<b>Finish: </b>'. get_field('finish_img', 'pa_metal-finish'.'_'.$term->term_id);
}
}
}
With use of the Wysiwyg Editor for image upload