private async Task SendReportMailWithHeaderImageAsync(IEnumerable <NinjaDTO> data, string emailAddress)
    {
        var headerImagePath = string.Format("{0}/{1}", _environment.WebRootPath, "images/mail-header-solid.png");

        var mailingModel = new MailContentDTO();

        mailingModel.HeaderImage = new LinkedResource
        {
            ContentId   = "header",
            ContentPath = headerImagePath,
            ContentType = "image/png"
        };

        mailingModel.HtmlContent = await GetGridContentAsync(data);

        _mailingService.Send(emailAddress, "Your Report", mailingModel);
    }