CIMDisk::DeleteBackgroundFile

static function DeleteBackgroundFile($userId, $fileId)
{
	$folderModel = self::GetBackgroundFolderModel($userId);
	if (!$folderModel)
	{
		return false;
	}

	$fileModel = BitrixDiskFile::getById($fileId);
	if (!$fileModel || $fileModel->getParentId() != $folderModel->getId())
	{
		return false;
	}

	$fileModel->delete($userId);

	return true;
}