How to embed images in email

I need to embed an image in e-mail. How do I do it?

I do not want to use third party tool, nor am I interested in language specific answer (but it is PHP, in case you are wondering).

I am merely interested in format of resulting e-mail body.

As you are aware, everything passed as email message has to be textualized.

• You must create an email with a multipart/mime message.
• If you're adding a physical image, the image must be base 64 encoded and assigned a Content-ID (cid). If it's an URL, then the <img /> tag is sufficient (the url of the image must be linked to a Source ID).

A Typical email example will look like this:

From: foo1atbar.net
To: foo2atbar.net
Subject: A simple example
Mime-Version: 1.0
Content-Type: multipart/related; boundary="boundary-example"; type="text/html"

--boundary-example
Content-Type: text/html; charset="US-ASCII"

... text of the HTML document, which might contain a URI
referencing a resource in another body part, for example
through a statement such as:
<IMG SRC="cid:foo4atfoo1atbar.net" ALT="IETF logo">

--boundary-example
Content-Location: CID:somethingatelse ; this header is disregarded
Content-ID: <foo4atfoo1atbar.net>
Content-Type: IMAGE/GIF
Content-Transfer-Encoding: BASE64

R0lGODlhGAGgAPEAAP/////ZRaCgoAAAACH+PUNv
cHlyaWdodCAoQykgMTk5LiBVbmF1dGhvcml6ZWQgZHV
wbGljYXRpb24gcHJvaGliaXRlZC4A etc...

--boundary-example--

As you can see, the Content-ID: <foo4atfoo1atbar.net> ID is matched to the <IMG> at SRC="cid:foo4atfoo1atbar.net". That way, the client browser will render your image as a content and not as an attachement.

Hope this helps.

the third way is to base64 encode the image and place it in a data: url

example:

<img src="data:image/png;base64,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" width="32" height="32">

Here is how to get the code for an embedded image without worrying about any files or base64 statements or mimes (it's still base64, but you don't have to do anything to get it). I originally posted this same answer in this thread, but it may be valuable to repeat it in this one, too.

To do this, you need Mozilla Thunderbird, you can fetch the html code for an image like this:

1. Copy a bitmap to clipboard.
2. Start a new email message.
3. Paste the image. (don't save it as a draft!!!)
4. Double-click on it to get to the image settings dialogue.
5. Look for the "image location" property.
6. Fetch the code and wrap it in an image tag, like this:

You should end up with a string of text something like this:

<img src="data:image/png;base64,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" alt="" height="211" width="213">

You can wrap this up into a string variable and place this absolutely anywhere that you would present an html email message - even in your email signatures. The advantage is that there are no attachments, and there are no links. (this code will display a lizard)

A picture is worth a thousand words:

Incidentally, I did write a program to do all of this for you. It's called BaseImage, and it will create the image code as well as the html for you. Please don't consider this self-promotion; I'm just sharing a solution.

Correct way of embedding images into Outlook and avoiding security problems is the next:

1. Use interop for Outlook 2003;

2. Create new email and set it save folder;

3. Do not use base64 embedding, outlook 2007 does not support it; do not reference files on your disk, they won't be send; do not use word editor inspector because you will get security warnings on some machines;

4. Attachment must have png/jpg extension. If it will have for instance tmp extension - Outlook will warn user;

5. Pay attention how CID is generated without mapi;

6. Do not access properties via getters or you will get security warnings on some machines.

    public static void PrepareEmail()
    {
        var attachFile = Path.Combine(
            Application.StartupPath, "mySuperImage.png"); // pay attention that image must not contain spaces, because Outlook cannot inline such images
   
        Microsoft.Office.Interop.Outlook.Application outlook = null;
        NameSpace space = null;
        MAPIFolder folder = null;
        MailItem mail = null;
        Attachment attachment = null;
        try
        {
            outlook = new Microsoft.Office.Interop.Outlook.Application();
            space = outlook.GetNamespace("MAPI");
            space.Logon(null, null, true, true);
   
            folder = space.GetDefaultFolder(OlDefaultFolders.olFolderSentMail);
            mail = (MailItem) outlook.CreateItem(OlItemType.olMailItem);
            
            mail.SaveSentMessageFolder = folder;
            mail.Subject = "Hi Everyone";
            mail.Attachments.Add(attachFile, OlAttachmentType.olByValue, 0, Type.Missing); 
            // Last Type.Missing - is for not to show attachment in attachments list.
   
            string attachmentId = Path.GetFileName(attachFile);
            mail.BodyFormat = OlBodyFormat.olFormatHTML;
   
             mail.HTMLBody = string.Format("<br/><img src=\'cid:{0}\' />", attachmentId);
   
            mail.Display(false);
        }
        finally
        {
            ReleaseComObject(outlook, space, folder, mail, attachment);
        }
    }
   

Actually, there are two ways to include images in email.

The first way ensures that the user will see the image, even if in some cases it’s only as an attachment to the message. This method is exactly what we call as “embedding images in email" in daily life.
Essentially, you’re attaching the image to the email. The plus side is that, in one way or another, the user is sure to get the image. While the downside is two fold. Firstly, spam filters look for large, embedded images and often give you a higher spam score for embedding images in email (Lots of spammers use images to avoid having the inappropriate content in their emails read by the spam filters.). Secondly, if you pay to send your email by weight or kilobyte, this increases the size of your message. If you’re not careful, it can even make your message too big for the parameters of the email provider.

The second way to include images (and the far more common way) is the same way that you put an image on a web page. Within the email, you provide a url that is the reference to the image’s location on your server, exactly the same way that you would on a web page. This has several benefits. Firstly, you won’t get caught for spamming or for your message “weighing” too much because of the image. Secondly, you can make changes to the images after the email has been sent if you find errors in them. On the flip side, your recipient will need to actively turn on image viewing in their email client to see your images.

Generally I handle this by setting up an HTML formatted SMTP message, with IMG tags pointing to a content server. Just make sure you have both text and HTML versions since some email clients cannot support HTML emails.