Click here to Skip to main content
15,860,943 members
Articles / Desktop Programming / Windows Forms
Article

Embed HTML Email Images

Rate me:
Please Sign up or sign in to vote.
4.74/5 (10 votes)
5 Jun 20072 min read 235.4K   1.2K   84   28
How to embed images in your email newsletter.

Other projects you will need to download

Screenshot - PSH_Ne2.png

Introduction

How to embed images into an email; short and sweet, but this is all this does.

Background

My sister wanted to send out an email newsletter and wanted to embed images. So, she asked a friend and they sent her some classic ASP code. Then she asked me to make it work. Yeah, right! I fired up VS 2003 and got a hold of MIL HTML Parser and DotNetOpenMail. Within an hour, I had a small little app that could take a webpage, add all the needed images, and change the img tags to point to the content IDs of the images attached to the email and send it off to an email address.

Using the code

This code is really straightforward. Just select an HTML file that you have created, add a subject, a "from" email address, a "to" email address and the SMTP server name or IP address, and then click Send. But what does the code do? Well, you can't get much simpler than this. The code goes off and gets all the img elements.

C#
// Get All the img nodes
GetImageNodes(document.Nodes);
private void GetImageNodes(HtmlNodeCollection nodes)
{
    foreach (HtmlNode node in nodes)
    {
        HtmlElement element = node as HtmlElement;
        if (element != null)
        {
            if (element.Name.ToLower() == "img")
            {
                imageNodes.Add(element);
            }
            if (element.Nodes.Count > 0)
            {
                GetImageNodes(element.Nodes);
            }
        }
    }
}

Then all the needed images are attached and the src attributes of the img elements are set to the content ID of the attached images.

C#
// Change all the img nodes
foreach (HtmlElement element in imageNodes)
{
    FileInfo imageFileInfo = new FileInfo(Path.Combine(
        fileInfo.DirectoryName,
        element.Attributes["src"].Value));
    string contentId =
        imageFileInfo.Name.Replace(imageFileInfo.Extension,
        string.Empty);

    if (!images.ContainsKey(element.Attributes["src"].Value))
    {
        // Add Image to the Email
        images.Add(
            element.Attributes["src"].Value, imageFileInfo.FullName);
        FileAttachment relatedFileAttachment =
                       new FileAttachment(imageFileInfo, contentId);
        if ((imageFileInfo.Extension == ".jpg") ||
            (imageFileInfo.Extension == ".jpeg"))
        {
            relatedFileAttachment.ContentType = "image/jpeg";
        }
        else if (imageFileInfo.Extension == ".gif")
        {
            relatedFileAttachment.ContentType = "image/gif";
        }
        emailMessage.AddRelatedAttachment(relatedFileAttachment);
    }

    //Change the src to "cid:<CONTENTID>"
    element.Attributes["src"].Value = string.Format("cid:{0}", contentId);

}

And then the changed HTML is added to the email message and sent off.

C#
// set the email text to the changes html
emailMessage.HtmlPart = new HtmlAttachment(document.HTML);

emailMessage.Send(new SmtpServer(this.SmtpServerTextBox.Text));

Points of interest

I just slapped this code together in an hour. In fact, writing the article added another 30 minutes. So, this is not code to look to for best practices. I just wanted to embed images into an email with a minimum of hassle and I achieved that goal with this. I hope others will find it useful.

History

  • 5/6/2007 - Version 2.0
  • 27/9/2005 - Version 1.0 - Also happens to be my birthday! :D

License

This article has no explicit license attached to it but may contain usage terms in the article text or the download files themselves. If in doubt please contact the author via the discussion board below.

A list of licenses authors might use can be found here


Written By
Grosvenor Financial Services Group Ltd.
New Zealand New Zealand
This member has not yet provided a Biography. Assume it's interesting and varied, and probably something to do with programming.

Comments and Discussions

 
Questionbackground images Pin
tianmingkun23-May-06 0:02
tianmingkun23-May-06 0:02 
AnswerRe: background images Pin
KiwiPiet4-Jun-06 15:56
KiwiPiet4-Jun-06 15:56 
Generalthanks Pin
dwatkins@dirq.net4-Oct-05 6:47
dwatkins@dirq.net4-Oct-05 6:47 
GeneralRe: thanks Pin
KiwiPiet4-Oct-05 9:44
KiwiPiet4-Oct-05 9:44 
Generaleven birthday to me.... Pin
jreddy26-Sep-05 16:37
jreddy26-Sep-05 16:37 
GeneralRe: even birthday to me.... Pin
KiwiPiet27-Sep-05 0:05
KiwiPiet27-Sep-05 0:05 
QuestionPNG? Pin
The_Mega_ZZTer26-Sep-05 14:50
The_Mega_ZZTer26-Sep-05 14:50 
AnswerRe: PNG? Pin
KiwiPiet27-Sep-05 0:12
KiwiPiet27-Sep-05 0:12 
yea cool I agree, but it was a quick and dirty to get something to work and I posted it just in case somebody else wants to or has been wondering how to do this. Like I said, this article is not about best practices I had to fit it in with a lot of other work so the priority wasn't a sparkling well written app, it needed to work and it needed to work in an hour.

I have had a request to expand it so that you can import an email list and email it off from the form. When I do that I will clean the code and repost it.

Thanks for your comments though, I will incorporate it.

General General    News News    Suggestion Suggestion    Question Question    Bug Bug    Answer Answer    Joke Joke    Praise Praise    Rant Rant    Admin Admin   

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.