// Previous/next page navigation.
the_posts_pagination( array(
'prev_text' => __( 'Previous page', 'twentyfifteen' ),
'next_text' => __( 'Next page', 'twentyfifteen' ),
'before_page_number' => '<span class="meta-nav screen-reader-text">' . __( 'Page', 'twentyfifteen' ) . ' </span>',
) );
$attachments = get_children(array('post_parent' => $post->ID,
'post_status' => 'inherit',
'post_type' => 'attachment',
'post_mime_type' => 'image',
'order' => 'ASC',
'orderby' => 'menu_order ID'));
foreach($attachments as $att_id => $attachment) {
$full_img_url = wp_get_attachment_url($attachment->ID);
// Your Code here
}