呼呼，总算搞定了，花了好几天时间啊>_<
网上很多关于JMail发送邮件的例子都没有写如何发附件，或者没有写清如何发内嵌的附件（比如把附件图片嵌入到HTML信件里面）
郁闷到极的时候终于“柳暗花明”，噢yeah~~！！！
其实最关键的就是这句要注释掉
'JMail.ContentType = "text/html"
(为什么要发内嵌的附件图片？因为如果是img src=网上的地址，在outlook等客户端内则显示是难看的“X”，需要手动下载图片)
本例子参考了Dimac(w3JMail官方)的样例，文件地址：
C:\Program Files\Dimac\w3JMail4\Examples\ASP\htmlimage.asp
(安装了Jmail的都有)
例子代码：
<%
'*************************************************
'* *
'* Produced by Skyhe.Com *
'* *
'* Code Written by Kittow at 2005-11 *
'* http://www.skyhe.com *
'* Mail:kittow_AT_263.net *
'* *
'* *
'*************************************************
Set JMail = Server.CreateObject("JMail.Message")
'是否将信头编码成iso-8859-1字符集. 缺省是True
JMail.ISOEncodeHeaders = True
'如果JMail.silent设置为true,ErrorCode包含的是错误代码
JMail.Silent = True
'设置标题和内容编码，如果标题有中文，必须设定编码为gb2312
JMail.Charset = "gb2312"
'JMail.ContentType = "text/html" '如果发内嵌附件一定要注释掉这行，重要！
JMail.From = "web@mail.skyhe.com" ' 发送者地址
JMail.FromName = "Skyhe System" ' 发送者姓名
JMail.MailServerUserName = "web" ' 身份验证的用户名
JMail.MailServerPassword = "123456" ' 身份验证的密码
'加入新的收件人
JMail.AddRecipient "kittow@mail.skyhe.com", "Mr.Example"
'JMail.AddRecipientBCC Email '密件收件人的地址
'JMail.AddRecipientCC Email '邮件抄送者的地址
JMail.Subject = "图片测试！！！"
JMail.Body = "A nice picture if you can read HTML-mail."
'增加一个普通附件
JMail.AddAttachment(Server.MapPath("images/email.gif"))
'增加一个嵌入式附件
' The return value of AddAttachment is used as a
' reference to the image in the HTMLBody.
'contentId = JMail.AddAttachment(Server.MapPath("images/email.gif"))
Dim contentId
contentId = JMail.AddAttachment("E:\images\email.gif")
'只有HTML格式支持嵌入图片附件，我们采用HTML格式的邮件内容
' As only HTML formatted emails can contain inline images
' we use HTMLBody and appendHTML
JMail.HTMLBody = "<html><body><font color=""red"">Hi, here is a nice picture:</font><br>"
JMail.appendHTML "<img src=""cid:" & contentId & """>"
JMail.appendHTML "<br><br> good one huh?</body></html>"
'如果对方信箱不支持HTML格式邮件，我们仍需要给他一个友善的提示
' But as not all mailreaders are capable of showing HTML emails
' we will also add a standard text body
JMail.Body = "Too bad you can't read HTML-mail."
JMail.appendText " There would have been a nice picture for you"
JMail.Send( "mail.skyhe.com" )
JMail.Close()
Set JMail = Nothing
%>