Ninja Forms Image Attachments

// remove ninja forms handling of featured image
add_action ( 'init', 'kia_tweak_ninja_forms' );
function kia_tweak_ninja_forms(){
    remove_action( 'init', 'ninja_forms_register_set_featured_image' );
}

// attach ALL the uploaded images
add_action( 'ninja_forms_create_post', 'ninja_forms_prepare_attach_uploads' );
function ninja_forms_prepare_attach_uploads( $post_id ){
    global $ninja_forms_processing;
    $upload_id = '';
    foreach( $ninja_forms_processing->get_all_fields() as $field_id => $user_value ){
        $field_row = ninja_forms_get_field_by_id( $field_id );
        $field_type = $field_row['type'];
        $field_data = $field_row['data'];
        if( $field_type == '_upload' ){

            $set_featured_image = isset( $field_data['featured_image'] ) AND $field_data['featured_image'] == 1  ? TRUE : FALSE;

            $upload_id = $field_id;

        }
    }
    if( $upload_id != '' ){

        $user_value = $ninja_forms_processing->get_field_value( $upload_id );

        $counter = 1;
        if ( $user_value ) foreach ( $user_value as $user_value ){
            $file_name = $user_value['file_path'].$user_value['file_name'];

            $feature_this = ( 1 == $counter && $set_featured_image ) ? TRUE: FALSE;

            ninja_forms_attach_uploads( $post_id, $file_name, $feature_this );

            $counter++;
        }

        // hard-coded, if more than 1 image attached add category id=66, 'submitted-gallery'
        if ( $counter > 1 && in_category( 65, $post_id ) ) {
                wp_set_post_categories( $post_ID, array( 65, 66 ) );
                // also change the post format
                set_post_format( $post_id, 'gallery' );
            }

    }
}

function ninja_forms_attach_uploads( $post_id, $filename, $feature_this ) {
    $wp_filetype = wp_check_filetype( basename( $filename ), null );
    $attachment = array(
        'post_mime_type' => $wp_filetype['type'],
        'post_title' => preg_replace( '/\.[^.]+$/', '', basename( $filename ) ),
        'post_content' => '',
        'post_status' => 'inherit'
    );
    $attach_id = wp_insert_attachment( $attachment, $filename, $post_id );
    // you must first include the image.php file
    // for the function wp_generate_attachment_metadata() to work
    require_once(ABSPATH . "wp-admin" . '/includes/image.php');
    $attach_data = wp_generate_attachment_metadata( $attach_id, $filename );
    if ( wp_update_attachment_metadata( $attach_id,  $attach_data ) && $feature_this ) {
        // set as featured image
        update_post_meta($post_id, '_thumbnail_id', $attach_id);
    }
}