css中的LinkedResource

我正在尝试用HTML正文发送电子邮件。 我在这个网站和其他地方找到了很多例子,很好地解释了如何使用 LinkedResource 类型的HTML标签的类 IMG .

在我的情况下,我有以下代码:

<table id="page" style="border: 2px solid #ff0000; ">
    <tr>
        [...]
    </tr>
</table>

和以下样式表:

    #page {
        width: 100%;
        height: 100%;
        top: 0;
        right: 0;
        background: url(https://www.example.com/img/bg.jpg) no-repeat center center;
        position: fixed;
        z-index: -1;
        -webkit-background-size: cover;
        -moz-background-size: cover;
        -o-background-size: cover;
        background-size: cover;
    }

下面是代码:

MailMessage mail = new MailMessage();
AlternateView plainView = AlternateView.CreateAlternateViewFromString( plainTextMessage, Encoding.UTF8, "text/plain" );
mail.AlternateViews.Add( plainView );
AlternateView htmlView = AlternateView.CreateAlternateViewFromString( htmlTextMessage, Encoding.UTF8, "text/html" );
mail.AlternateViews.Add( htmlView ); 
mail.Body = htmlTextMessage;  
mail.IsBodyHtml = true;
mail.To.Add( new MailAddress( customer.Email, customer.FullName ) );
mail.From = new MailAddress( "noreply@example.com", "My Web site" );

SmtpClient client = new SmtpClient();
client.Send( mail );

如何使用LinkedResource类嵌入背景图像?