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How to best employ embedded images in an email


Transactional emails can be spruced up with images embedded in them. Emails that have embedded images not only share knowledge but critically engage the users in a better manner. However, If it is not handled well, embedding images in an email can negatively affect the deliverability, engagement and sender reputation. Email Marketing

The email could have multiple images or even just the logo, helps establish a sense of legitimacy in what you are sending out. However, a crucial limitation comes with embedded email in using an emoticon or emoji and can be tricky if not handled carefully. Most email clients set the default status of delivered messages to block images to safeguard the interests of users. Because of this default status, a user ends up seeing a large, white space (along with your image alt or title text if you’ve included it) and often a message to right click the image(s) in order to download. Hence, it is important to use the right method to embed the images in an email.

Different methods of embedding images in email

Senders, today, have three different methods to embed images in an email, viz., CID tags, inline embedding and linked images. But before using these methods, one should take a closer look at their recipient’s behavior and which method suits their emailing pattern.

CID embedding

CID images (or Content-ID) has been used for a pretty long time to send media via email. Though outdated, it’s still a viable option.

CIDs are pretty easy to use when it comes to an email. You just attach the intended image to the email and reference it with HTML tag in the email’s template, embedding the image when opened.

Though using CIDs may sound simple, the actual process can be fairly complicated one, with mixed results. For example, CIDs work well with desktop email clients, but they do not play well with browser-based emails. Additionally, embedding images in this manner increases the size of your overall email, which can hinder deliverability.

The following image can help you understand the concept of CID Embedding –

How to best employ embedded images in an email

As it is evident, an image is selected from the database and embedded in the email message.

Inline image mail

In comparison to the CID technique, inline embedding offers a simpler solution to embedding images. On the downside, however, it’s not as versatile as CID and has a similar problem of increasing the email size.
Inline embedding technique demands you to have a base64, a type of string encoding scheme, of your image. With this encoding string, simply embed your image into your email through a standard HTML tag. It requires no further investigation into MIME or code.

How to best employ embedded images in an email

In the above screenshot, the image is pasted in the mail body itself. This is commonly referred to as Inline image embedding. The only drawback is that inline embedding does not function well with webmail services and gets blocked completely by Microsoft Outlook.

Embedded images do not evade image blocking, majority of email services display embedded images. However, there are email services that block images by default. Here is a look at which email services display embedded images and which do not.

Email Clients Embedded image displayed Comments
iOS Mail Yes
Outlook 2003 Yes All images blocked by default (Hotmail) No Grey ‘blocked image’ placeholder displays, no ALT text

All images blocked by default

Yahoo! Mail No Placeholder and ALT text display

All images blocked by default

Gmail No Placeholder and ALT text display

All images blocked by default

Android default Yes All images blocked by default


Linked images embedding

The third technique is linked images. Unlike, the CID and inline image embedding techniques, linked images are simple to implement and light on email size. The one complication that could arise out of this technique is based on the number of recipients who will receive the image-laden emails.

Fundamentally, CDN hosts your images across a network of data centers. Emails designed with an embedded image in mind will then call on this CDN-hosted image through an embedded HTML tag. Thus, linked image embedding is simple, keeps email lightweight and also allows you to tweak the image through required changes to its HTML tags. However, using linked images do have a few downsides, viz.; it requires an email to download the embedded image(s) from external servers, which could lead to latency issues at the receiver’s end.

Our recommendation

An understanding of the 3 methods of image embedding has allowed us to weigh out its benefits and drawbacks. Out of the three, Linked images are the most preferred and recommended one in email marketing.

  1. As it reduces the email message size
    2. Web-mail clients are becoming smarter now. They cache the image on first load, so that it will not take time in second load.

Always check the text to image ratio. If your email has too much text, and just one or two small images like the company logo or an image in the signature, or just one fancy button. Then it is preferred to use CID images. If it contain more images like a Product catalog or newsletter then it is recommended to use linked images.

Regardless of what embedding technique you employ, you’ll need to have an understanding of who is going to access your email and how they will look at it. Accordingly, your design team will need to prepare & design email images for different delivery platforms like, mobile, desktop and web browsers, to facilitate the endless supply of email services.

So, make sure you use the following rules to deliver emails properly:

  • Alt and Title Text Rule:This text is contained within the embedded image URL, appearing when the image doesn’t load or when one hovers the mouse over the image. It is necessary to have this text beneath the image(s) as it lets you convey the message intended through the image even if it doesn’t load.
  • No trapped messages Rule:If it’s important that your readers know a piece of information, it should not be trapped in an image. If those intended messages are in image form, you’ll have users looking for information, but possibly not finding it. Instead, such messages should be HTML buttons.

Most people spend less than a minute scanning an email before they decide whether to read it or delete it. If your email is laden with many images, the user won’t see much that allows them to make a decision.

Pepipost is one of the most preferred transactional email delivery platforms. It is liked by users for its cost-effectiveness and dynamism. We can help you choose the best way to embed images in the email.

    Akshay Tiwari | Digital Marketer, Pepipost

    Akshay Tiwari
    Digital Marketer, Pepipost
    Akshay is an avid digital marketer passionate about new and emerging technologies. He is experimental and on the constant lookout to integrate new techniques in his working style. His one true love is football and is a very active player. He is also an appreciator of arts and finely appreciates them.


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