mandatory picture upload snipped does not work since upload

Since update the following Code snipped leads to a bug when uploading picture in form:

add_filter( "adverts_form_load", "customize_adverts_add" );

function customize_adverts_add( $form ) {
    if( $form['name'] != "advert" ) {
        return $form;
    }

    adverts_form_add_validator("gallery_has_image_uploaded", array(
        "callback" => "gallery_has_image_uploaded",
        "label" => "",
        "params" => array(),
        "default_error" => "Please upload at least one picture",
        "validate_empty" => true
    ));

    foreach( $form["field"] as $key => $field ) {
        if( $field["name"] == "gallery" ) {
            $field["validator"] = array(
                array(
                    "name" => "gallery_has_image_uploaded"
                )

            );
        }
        $form["field"][$key] = $field;
    }

    return $form;
}

function gallery_has_image_uploaded( $value ) {
    $post_id = adverts_request( "_post_id" );
    $media = get_attached_media( 'image', $post_id );
    if( count( $media ) > 0 ) {
        return true;
    } else {
        return false;
    }
}