WordPress - Insert one post per image attachment

index.php

<?php
$posts = get_posts( array(
    'post_type' => 'attachment',
    'post_mime_type' => 'image',
    'posts_per_page' => -1
) );

foreach ($posts as $key => $value) {
    $post_id = wp_insert_post( array(
        'post_type' => 'new_post_type'
    ) );

    var_dump( set_post_thumbnail( $post_id, $value->ID ) );
}