// first you do a query for attachments looking for the exact image_meta_image_id
$args = array(
'fields' => 'ids', // return only IDs to use in the next query
'posts_per_page' => 1, // there should only be one image
// with this "image_meta_image_id"
'post_type' => 'attachment',
'meta_query' => array(
array(
'key' => 'image_meta_image_id',
'value' => $image_meta_image_id
)
)
);
$attachment_query = new WP_Query();
$attachments = $attachment_query->posts();
// now you need to do a query to get all of the posts what use that attachment
// if it was found
if (!empty($attachments)) {
$args = array(
'post_type' = 'your post type',
'posts_per_page' => -1,
'meta_query' => array(
array(
'key' => 'gallery field name',
'value' => '"'.$attachments[0].'"',
'compare' => 'LIKE'
)
)
);
} // end if attachments found
