test.php

<?php
/*
Template Name: Test
*/
 
get_header();
 
?>
 
<div id="main-content">
 
<?php 

$terms = ( isset( $_GET['styles'] ) ) ? $_GET['styles'] : 'formal';

$args = array(
	'post_type' => 'attachment',
	'post_status' => 'any',
	'tax_query' => array(
		array(
			'taxonomy' => 'media_category',
			'field' => 'slug',
			'terms' => 'formal'
		)
	)
);

$the_query = new WP_Query( $args );

$categories = array();

if ( $the_query->have_posts() ) 

	while ( $the_query->have_posts() ) {

		$the_query->the_post();
		$custom_url = get_post_meta( get_the_ID(), '_gallery_link_url', true );
		$custom_image_alt = get_post_meta( get_the_ID(), '_wp_attachment_image_alt', true );
		echo '<a href="' . $custom_url . '" target="_blank" title="' . $custom_image_alt . '" alt="' . $custom_image_alt . '" >' . wp_get_attachment_image( get_the_ID(), 'thumb' ) . '</a>';
		get_post_meta( get_the_ID(), '_wp_attachment_image_alt', true );

		$categories[] = wp_get_post_terms( get_the_ID(), 'media_category' );

	}

}
?>
<ul class="styles">
	<?php foreach ( $categories as $category ) : ?>
		<a href="?style=<?php echo $category['slug']; ?>">
			<?php echo $category['name']; ?>
		</a>
	<?php endforeach; ?>
</ul>

<form name="jump">
        <select name="menu">
            <?php
              while ($the_query->have_posts()) : $the_query->the_post(); ?>
                <option value="<?php the_permalink() ?>"><?php the_title(); ?></option>
                <?php
              endwhile;
            
            ?>
        </select>
        <input type="button" onClick="location=document.jump.menu.options[document.jump.menu.selectedIndex].value;" value="Go">
    </form> 
 
 
<?php wp_reset_postdata(); ?>
 
</div> <!-- #main-content -->
 
<?php get_footer(); ?>