API

Something like this:

<?php 

$args = array (
	'post_type' => 'attachment',
	'post_status' => 'any',
	'posts_per_page' => -1,
	'tax_query' => array(
		'relation' => 'AND',
		array(
			'taxonomy' => 'YOUR_TAXONOMY_NAME',
			'field' => 'slug',
			'terms' => 'YOUR_TAXONOMY_TERM_NAME'
		),
		array(
			'taxonomy' => 'category',
			'field' => 'slug',
			'terms' => 'YOUR_CATEGORY_NAME'
		)
	)
);
$the_query = new WP_Query( $args );

if ( $the_query->have_posts() ) :

	while ( $the_query->have_posts() ) : $the_query->the_post(); 

            echo wp_get_attachment_image( get_the_ID(), "thumbnail");

      endwhile; 

endif;

wp_reset_postdata(); 

?>