How to make images display correctly in email signatures (not as attachments)

How to make images display correctly in email signatures (not as attachments)

How to make images display correctly in email signatures (not as attachments)

Displaying images as attachments is a common problem. The solution is not so obvious, because there can be many reasons for that. The problem may occur if the message gets converted to the plain text format or if there are issues with the HTML code of an email signature. Finally, it can be caused by a specific Outlook configuration. In this article, I will show you how to make sure images are not displayed as attachments in each of those situations.

Make sure the email format is set to HTML

The most common reason for images displaying as attachments is that some messages are sent in the plain text format instead of the HTML format. As the plain text format does not support embedding or viewing images, all images are automatically attached to the message.

Automatic format change can happen either because of Outlook or Exchange Server settings:


In Outlook 2010, 2013 and 2016 you can set all messages to be sent in HTML by default.

Just go to File > Options > Mail > Compose messages and set Compose messages in this format option to HTML.

email signatures with images display correctly in email signatures - not as attachments set HTML as default

For Outlook 2007, go to Tools > Options > Mail Format. Then, from the list which is next to Compose in this message format, choose HTML.

Remember that in the case of replies and forwards, the default message format is the same as in the original message. As a result, if you want to respond to a plain text message, you have to change the message format manually by clicking Format Text tab on the ribbon and choosing HTML.

email signatures with images display correctly in email signatures - not as attachments HTML format

If you compose a message in the reading pane, be sure to click Pop Out button first:

images display correctly in email signatures - not as attachments Pop Out

Note that in Outlook there is an option to receive all messages in the plain text format. The side-effect of setting this option on is that all replies and forwards are also in this format by default. If you want to know how to turn this option off, go to The receiver converts all messages to the plain text format.

On-premises Exchange Server and Office 365

Your Exchange Server might convert outbound messages to the plain text format. It can happen on every on-premises Exchange Server, as well as on Office 365 with Exchange Online. By default, all messages are converted to the HTML format, unless they are originally in the plain text format – in which case they continue to use simple text formatting. However sometimes, especially in Office 365, some HTML-formatted messages are converted to plain text anyway. As it happens on the server level, it cannot be influenced by Outlook. Luckily, there is a PowerShell cmdlet which lets you change this Exchange policy quickly:

Get-RemoteDomain | Set-RemoteDomain –ContentType MimeHtml

This cmdlet should work on all emails sent outside the organization, converting them to use HTML formatting.

The receiver converts all messages to the plain text format

Another option is that it is the recipient’s fault. MS Outlook and some security programs may convert all messages to plain text automatically. If it is Outlook, above the message there will be a note that “This message was converted to plain text.” The message can be converted to HTML format by clicking the Infobar and choosing Display as HTML:

email signatures with images display correctly in email signatures - not as attachments convert to html

Automatic email conversion can be turned off in Trust Center settings under E-mail Security tab, Read all standard mail in plain text, by checking off the checkbox:

images display correctly in email signatures - not as attachments plain text

However, if you are the sender of the message, you do not have much influence on those settings on the recipient’s side.

Match the HTML display size and the actual image size

First of all, Outlook is known for having a unique way of interpreting HTML code. One of the effects can be displaying images as attachments, and not showing them in the message. This may happen if the width and height parameters of an image are not the same as actual image size. Because of that, you have to make sure that your HTML email signature does not have such differences. Ensure your pictures have the right resolution and resize them if necessary (You can use any image editor, like Paint, GIMP, or Photoshop). Then, add the width and height tags corresponding to the dimensions of the image.

How to edit the HTML file of an email signature

Email signature editor in Outlook does not let you modify the source HTML code. There is an easy way to edit Outlook email signatures, though:

  1. If you have a signature created in Outlook, go to mail options and click Signatures… while holding the Ctrl key:
    images display correctly in email signatures - not as attachments edit signatures
  2. A window with your defined signatures will open. To edit the one you want, right-click it and choose a simple text editor like notepad. (For your convenience, you could also use a more advanced code editor, like Notepad++).
    images display correctly in email signatures - edit with notepad
  3. Now all that is left is to find your img tag and change width and height attributes, if necessary.
    images display correctly in email signatures - edit with notepad 2

Linked images are sent as embedded

This problem occurs mostly in the older versions of Outlook (Outlook 2007 and Outlook 2010), but can also happen in Outlook 2013 and 2016 if some settings were migrated, or if someone changed the Outlook configuration.

Usually, linked images should not become attachments – that’s one of the differences between linked and embedded images (More differences in Images in email signatures – linked or embedded?). However, sometimes Outlook automatically downloads linked pictures and embeds them in the message. To change that behavior, you have to make some changes in the registry.

Note: Be careful when editing the registry, as it is easy to harm your computer or programs you use if you are not sure what you are doing. Be sure to always backup your registry before applying any changes.

  1. First, start Regedit with “Win + R” key combination and typing in Regedit.
    images display correctly in email signatures - not as attachments regedit
  2. The path you need to access is:


Note X stands for the Outlook version you have, e.g. if you have Outlook 2016, it would be 16.0

images display correctly in email signatures - not as attachments registry

When you access this location, you either have to find or add Send Pictures With Document REG_DWORD key and change its value to 0.

Thanks to that, the pictures will not be downloaded by your Outlook before the message is sent.

A different approach

If you find troubleshooting troublesome (and, by definition, it usually is), you could take a different approach, which makes images display correctly in email signatures every time. Images are not blocked by the recipients’ Outlook (unless they view emails in plain text only), nor are they displayed as attachments. The solution is a third party tool for Office 365 or Exchange Server.

Regardless of the platform, email signatures are added on the server level, which renders issues with email clients irrelevant.

You can add images with a single button and decide whether you want to embed them, or add them as linked pictures (see this article for differences between linked and embedded images). Either way, the images will not be displayed as attachments.

add picture to email signature CodeTwo

To learn more about those third party tools, click on the links below:

Further reading:

29 thoughts on “How to make images display correctly in email signatures (not as attachments)

  1. Monitors

    Such a great information. This is really very helpful for bloggersSuch a great information. This is really very helpful for bloggers

  2. Jeff Carbine

    I like what you said the most common cause for photos showing up as attachments is that some communications are delivered in plain text rather than HTML. This is a good article having a lot of knowledge of graphics would be a good part for me as a computer student. I wanted to thank you for your explanation.

  3. Tom Geldner

    Came across this just now and have a few observations based on my years of struggling with Outlook signatures.

    1. The best way you can do an HTML signature is via an external HTML editor (Dreamweaver or even notepad). If you use Outlook (any version) to do it, you will get a hideous amount MS specific code because Outlook draws on the MS Word HTML editing function.
    2. If you use CSS in your signature, make sure it’s all INLINE CSS so it’s confined to the signature itself unless you are hosting an external and publicly available stylesheet. Note that I personally don’t like doing this because it causes your email to load at different rates.
    3. If you include a graphic image with your signature, make sure the HTML reference to the image is local to the Signatures folder if you are embedding it AND the image is actually in the Signatures folder. NOTE – you may not see the image in the signature Preview window in Outlook. For example, if you embed the image, it should be located in C:\Users\USER\AppData\Roaming\Microsoft\Signatures
    4. I have found that embedded signatures will display correctly in a client computer 90% of the time while externally referenced ones maybe 75% of the time. The argument for “increased” file size is a non-starter with me since half the emails I get have attachments or huge amounts of tracking code that dwarf the size of most signature logos. Mine is 3K for example.
    5. The registry hack to “Send pictures with document” (using the value 1 for true) does not in my experience turn the graphic into an attachment with the exception of some mail programs that aren’t smart enough to display them in the body of the email. IF you set this value to 0, then you must use an externally linked and publicly available image file. FWIW, without this hack, I believe the Outlook default is to not send images with document anyway. I don’t believe that this registry entry is present in Outlook default installations from 2010 onward.

    Anyways, nice site. Who knew email sigs could be so complex?

    1. Kamil Glaser Post author

      Thanks for the insights!
      Ad 1 That’s one of the reasons why our free email signature generator came into being. It’s incredible what Outlook does to the code.
      Ad 2 Inline CSS is what we always recommend for email signatures.
      Ad 3 Good tip!
      Ad 4 We’ve posted a recent article about email signature size. If graphics are below 50 KB, it’s perfect. We’ve seen some 1MB+ banners though, which is definitely too much.
      Ad 5 The hack comes in handy mainly for older versions of Outlook (2010 is still widely used) and upgrading to a newer version may cause this strange setting to be migrated.

  4. Guido Neumann

    Hi, I want all received images in HTML emails to be shown as attachments. Sometimes they are shown inline, sometimes as an attachments. How to show it as an attachment, always?
    Thank you!

  5. Goof

    The company I now work for is considering migrating off GSuite to O365 for various reasons. (I don’t care to debate that.) Our signature in GMail includes an image and a link to a YouTube video. I’m not yet sure how this was set up, I simply copy/pasted from another user’s message into my GMail account signature and edited the text for my name etc., and it seems fine. However, a new person using Outlook (with GSSMO) cy/pasted and it’s not displaying the static image and video-link image properly. Any suggestions?

    –> And, best suggestions for the same topic company-wide for the migration to O365?

    Thanks, great write-up!

    1. Kamil Glaser Post author

      It’s hard to say what’s causing the signature issues without seeing the actual signature/its code. Using one of the templates from our free signature generator gives a reliable HTML code, which shouldn’t break even when changing email clients.
      When it comes to company-wide email signatures in Office 365, here’s an article on how to configure it.

  6. Harriett Kraasch

    There’s definately a great deal to find out about this subject. I love all of the points you have made.

  7. Matthew

    My signature in outlook is html its selected as html but i do a test email to a address and it appears fine.. appears perfect but its double two signautres

    ive tried searching and troubleshooting im using outlook for windows 10 any idea how to fix? or is it a protonmail bug/error?

    1. Kamil Glaser Post author

      Double email signatures could be caused by using Outlook email signature together with a global email signature. Generally, if you manage email signatures centrally with mail flow rules or a third party tool, it is usually best not to use any email signatures in email clients.
      If you are not managing email signatures, it could be double-pasted in the Outlook’s email signature editor.

  8. leib dodell

    Thanks for the article but the fact that I have to read through a long technical article to figure out how to put my logo in my email signature is so utterly and preposterously absurd it’s really difficult to put it into words. In fact if you had one opportunity to put something into a time capsule to sum up the misery of living with 2019 technology, you could not possibly do better than this article. There is but one reason and one reason only why it is difficult to get a logo to appear properly in an email signature — impossibly arrogant, lazy, clueless programmers who could not mathematically care any less about the user experience of the products they create. Ok rant over. But SERIOUSLY . . . .

    1. Hugh L. McManus 3.0

      Leib, your February 21, 2019 comment is quite simply my favorite post i have seen on the interweb!

    2. Bob

      SERIOUSLY????????? So by the same token you would expect to rebuild a car engine, or upgrade the wiring in your home without any/limited mechanical or electrical experience…. just by reading a free set of online instructions relating to a couple of car models.

      There are COUNTLESS reasons why emails are problematical for both programmers AND users. Yes, some are related to programming design (read: how much did YOU pay for your email client or free webmail browser?), but most are related to the complexity of internet use and certainly not laziness.

      If you really want ONE reason though; Spam. And that is why email is, and always will be, a nightmare. Pure and simple.

      I feel your frustration… I share it. But blame the spammers, not the programmers (well the legit ones anyway).

    3. John

      I understand your frustration but its because you are ignorant to the way email and the internet works. Its not because of lazy clueless programmers. The technology that runs the internet, email, your smart phone and so many other things you take for granted that make up your life are very complex systems designed by smart and clever people.

      Most technology has and continues to be simplified, to the point where regular users expect all things to be simplistic and instantly intuitive. This cultivates the belief that everything should and has to be this way. However the complex systems that run everything you take for granted are coated in a thin facade of simplicity for the sake of the general population.

      You have no idea how email works, how email signatures are designed, laid out, the code behind it or why it is like it is. You just want it to be easy and something you can understand quickly. It looks simple so should be.

      Honestly, It doesn’t really matter. You will continue to struggle with things like this and always will because your attitude is that everything should be simple and make sense for you. When it doesn’t its because other people are clueless lazy or, most ironically of all, arrogant.

      1. Goof

        John, very well stated. Just printing a pretty, colorful picture on a piece of paper from electrons displayed on a glowing rectangle is a minor miracle. People take this for granted all the time. Email has been abused to where it’s supposed to be far more than simple digital communication. Try explaining the nuances of DNS, SPF, DKIM and DMARC to an average person complaining about SPAM and watch their head spin. Blaming programmers for laziness and arrogance is a cheap shot from a place of ignorance. Sigh…

  9. renee

    I have a client who incorporates a graphic in their signature–every email i receive from her team shows as a message with an attachment. This makes it very inconvenient when i’m looking through messages in search of an attachment. What’s the fix for removing the signature graphic so when searching for attachments, these bothersome little signature graphics don’t show (paperclip)

    Many thanks for your help.

    1. Kamil Glaser Post author

      I am afraid there is not much you can do about those messages on your (the recipient’s) end – This behaviour is caused by the sender’s Outlook. You might advise the client to fix their signatures using this article.

  10. P

    Don’t the external images added to a signature get blocked initially by default in Outlook just like those from a marketing email causing more of an issue than just embedding it?


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