Using WP Plugin
Download and activate Disable Comments plugin. Using this plugin admins can easily disable comments site wide or according to post type. After installation it can be accessed from settings menu of admin area dashboard.
Using WP Hack
Add this code in your theme’s function.php file:
function filter_media_comment_status( $open, $post_id ) {
$post = get_post( $post_id );
if( $post->post_type == ‘attachment’ ) {
return false;
}
return $open;
}
add_filter( ‘comments_open’, ‘filter_media_comment_status’, 10 , 2 );