why not embed images in email

Showing images in an e-mail or HTML format still relies on hyperlinks. You've got to be able to link to something. Embedding the image would involve code describing what the image actually looks like in such a format that is supported by other e-mail applications. That's a lot of code, and can you imagine what it would look like if received as a text-based e-mail?

Sending an image as an attachment does not embed it in the e-mail.

There are a few "oddball" ways to do this, such as embedding an image in an Rich Text Format e-mail. However, I believe this capability is limited to Microsoft Outlook. (Try creating a signature line sometime in Outlook that utilizes an image. It's... interesting.) People using a e-mail application that doesn't support RTF e-mails won't be able to see the image.

Linking an HTML e-mail to an image offers the further advantage of keeping the e-mail file size small, thereby reducing downloading time. To the best of my knowledge, this is still the best way to go.

just to clear up a few things,

I am using MIME, so I can attach images and have them appear in the email, it is multipart/related format.

also, MIME specifies content-types, so attached images wouldn't be displayed in their binary form on a text email reader, they wouldn't appear at all in fact.

I would really like to know what email readers can support this type of tag <img src=CID:filename.jpg>

because this is the method for diplaying the images in the related part of the mime message.

the reason I ask is because I am distributing software to let people send an html email in some other program, and I believe it will be hard to sell this if they have to host the images on a website.

I know using the link to an webserver is fool proof(providing connection to internet), so I would use that unless I thought 99% of html email readers could see the images, and that it degraded gracefully in the last 1%

let me know what you think,

Thanks,
Bob

The main reason this has become the accepted practive is not technically driven at all. As you know anything is possible with bit of programming so the delivery of the images is not an issue.  The real reason behind linking to images is the ability to track the success rate of the email.  Each request for an image will be logged to the webserver that the image is sent from and you will be able to generate reports regarding the success of the email.  Prior to sending the email you should know the number of emails to be send and you can do a simple calculation to show the success rate of the email.  You would have to use a log analyzing utility (ie Webtrends) to determine the number of hits for each image and then divide that number by the total sent to see the percentage of emails that were actually viewed.  Most commercial emails that are sent are paid for by the marketing department and they alsways want to see reports to justify the amount paid.  If you aren't able to spend the money ($2k for webtrends) there are several free log analyzing utilities out there they do a great job and are totally customizable.   My personal favorite is http://www.analog.cx/.

So according to that logic, I should be embedding the images in the message, right? cause my customers don't need to track when the email is opened.
I was more concerned with it working on diverse systems.

Thanks again!
Bob

I'm sure this the exception rather than the rule, but I live in the boondocks and have dialup at home.  This means a slow modem connection and I keep HTML turned off in my email system (Outlook).  So I'd much rather get a link I can go to than have to download an image file without even knowing what size it is, what it is or who it is from.

The question was what is the usual practice not how to ensure proper display of an email with mulipile email systems.  However, not only is linking to the images the most widely accepted way to meet goals of an organization but it also affords the most flexibility to email readers.  If you embed the images within an email you are taking away from the ability of the individual email reader to interpret and handle the display with its own internal logic.  A simplified example of this the difference of some web pages when viewed with Netscape, Internet Explorer, and Opera.  Each program display the pages a little different but is reading the same code.  If you embed graphic certain email programs will not be able to handle them properly.  AOL for example has its own proprietary graphic format (.art) that will not display in most other programs without an update/patch.

@

Note that lot's of big-time players (such as Dell) routinely send HTML email newsletters with lots of images.

I guess it's good practice to offer CHOICE to the subscriber when they sign up - ask them do they want (a) NO email; (b) TEXT-ONLY email; or (c) HTML email (with images).  

@

okay that seemed good enough...I know other people said similar things...


I was really looking for someone to address the fact that it is very difficult for an end user to send an email in this manner!!

In outlook you can embed an email and it does get attached and embeded.
I guess microsoft figured it worked okay!!

well, it is easier for me not to embed them, but I still am not convienced that this is the correct solution.

Bob

If not to monitor what users are actually being able to read your HTML emails (embedded images), then you must take into consideration which email programs will, by default, even display your embedded image.

As many, if not most, malicious scripts pass through that of HTML based email, so many of the email clients today, including other protective applications, by default will not show embedded images as it's part and parcel with HTML code.  

From the publisher's point of view, I think it's important to use a mailing list type program that allows for opt-in subscription choices and one that can send out either regular text or HTML emails according to the recipients preference.  I personally have enjoyed DADA mail (formerly Mojo) just for those reasons.  See: <http://mojo.skazat.com/>

And from the user's point of view, by default both my Outlook Express and my Eudora only display text, regardless.  Actually I've enjoyed Eudora over the years just for this reason alone.   And to resolve the issue of me perhaps wanting to see the graphics and HTML, most smart publishers have a text link to a secondary web page loaded with all the graphics and color I'm missing.  

In short, it seems to me the important thing is to give your readers a choice.  And being that more and more Internet users are becoming Internet-Security savvy, if not forced by their own software first, and you want to reach the largest possible reading audience and to give them choices a well.  

Mark