If you want to stop Outlook from showing signature images as attachments, you’re in the right place.
This article will show you how to ensure images are not displayed as attachments in each situation.
If you’re ready to optimize your Outlook usage, check out the MySignature Office 365 integration for teams to ensure that emails look correct across your team.
Contents:
- Reasons why images added as attachments in Outlook, Gmail emails
- How to fix the displaying of images as attachments in Outlook in 2026
- How to ensure email signature images display not as attachments?
- FAQ
Reasons why images added as attachments in Outlook, Gmail emails
1) Email format: HTML vs Plain Text
One of the most common reasons is the email format. If the email is sent or opened as Plain Text instead of HTML, images cannot be embedded inside the message. In that case, Outlook treats them as file attachments.
2) Email client rendering differences
Different email clients handle images in different ways. Some clients insert the image inline, but still store it internally as an attachment. That’s why the image may look like an attachment even though it’s embedded.
Outlook, Apple Mail, and Thunderbird may show images inline for convenience, but technically they can still be attachments behind the scenes.
3) How the image was inserted
The way you add the image matters.
Pasting an image directly from File Explorer often makes Outlook treat it as an attachment. But using Insert → Picture… may embed it correctly.
Even small actions can change the result, you can try:
- Copy-paste vs Insert
- Copying from clipboard vs attaching from a file
- Set your email signature image to 96 DPI (read below about this moment).
So if your Outlook email image shows as an attachment, the insertion method is often the reason.
4) Outlook bugs and drafts behavior
Sometimes it’s not your fault at all. Some support articles mention Outlook bugs where images show as attachments after you save the message to Drafts, even if the images were inline at first.
5) Email signature images being added as attachments
Images inside an email signature can also cause this issue. Inline signature images may be treated as attachments and even duplicated. Outlook or plugins may rename these files and show them separately as attachments.
Some signature management systems also have settings that affect whether images are embedded or attached, which can change how your signature looks for recipients.
6) Recipient-side settings
In some cases, the issue happens on the recipient’s side. Their email client may convert incoming HTML emails into Plain Text, or decide to display images as attachments.
How to fix the displaying of images as attachments in Outlook in 2026
Use HTML Email Format (Not Plain Text)
If images keep showing up as attachments in Outlook, the most common reason is simple: the email is being sent in Plain Text instead of HTML.
Plain Text emails can’t embed images, so Outlook automatically treats them as attachments.
The fix is to make sure you’re writing and sending emails in HTML format.
Set Outlook to send emails in HTML by default
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.
For Outlook 2007, go to Tools > Options > Mail Format. Then, choose HTML from the list next to Compose in this message format.
Remember that the default message format is the same as the original message in the case of replies and forwards. As a result, if you want to respond to a plain text message, you must manually change the message format by clicking the Format Text tab on the ribbon and choosing HTML.
Note that Outlook offers an option to receive all messages in 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 part of this guide "The receiver converts all messages to the plain text format".
Check on-premises Exchange Server and Office 365
Your Exchange Server might convert outbound messages to the plain text format. It can happen on every Exchange Server and Office 365 with Exchange Online on-premises Exchange Server. By default, all messages are converted to the HTML format unless they are initially 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 that 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 HTML formatting.
Set your email signature image to 96 DPI
If your Outlook signature image still shows up as an attachment, the issue may be the image DPI and sizing.
For Outlook, the image resolution should be 96 DPI in most cases. The goal is to use the image in its true dimensions and actual resolution, without Outlook needing to “rebuild” it.
Step 1: Check the real size and DPI of the image
First, find the true dimensions and the actual resolution of the image.
If it’s not already 96 DPI, you’ll want to rescale it to 96 DPI (if necessary).
Step 2: Insert the 96 DPI image into your Outlook signature
After you have the correct 96 DPI version, insert the image into your signature.
This step is key.
If the image is embedded in its true dimensions (in HTML) and in 96 DPI, Outlook won’t mark it as an attachment.
But if the image properties inside the signature don’t match the original, Outlook may only keep a reference to the picture. That reference can be passed to the recipient as an attachment, which is why the image appears below the email.
Recipient-side fixing
Another option is that it is the recipient’s fault. MS Outlook and some security programs may automatically convert all messages to plain text. 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:
Automatic email conversion can be turned off in Trust Center settings under the E-mail Security tab, Read all standard mail in plain text by checking off the checkbox:
However, if you are the message's sender, you do not influence those settings on the recipient’s side.
How to ensure email signature images display not as attachments?
If you want to avoid issues with images in your Outlook email signature, consider using an email signature generator like MySignature. MySignature is a great option when you want signature images to display correctly (instead of showing up as messy Outlook attachments) and when you need one branded format across your whole team. It may not be necessary if you rarely use email or if your company needs very complex server-level signature customization.
FAQ
Why does my email signature logo appear as an attachment?
This can happen because your email signature includes an image file (like a PNG or JPEG). Since images are binary files, some email clients, especially Outlook, may treat them as attachments, even if the logo is supposed to display inline inside the signature.
How to ensure email signature images display and not as attachments?
To avoid images showing as attachments, create an HTML email signature and add your logo using an <img> tag that points to an image hosted online (using a direct URL). This way, the image displays inside the signature without being attached to the email.
How to put an image in an email (not as an attachment) in Outlook?
Click inside the email message body. Then go to the Insert tab, and in the Illustrations group, select Pictures. Browse to the folder where your image is saved, choose the file, and click Insert. After that, you can resize or rotate the image using the handles around it.
Why are images not displaying in email?
Many email clients let users block images by default for privacy and security reasons. Some inboxes also come preset to automatically disable certain types of images, so recipients won’t see them unless they choose to allow them.
If you’re adding an image manually in Outlook, make sure you insert it correctly:
Click inside the email message body. Then go to the Insert tab, and in the Illustrations group, select Pictures. Browse to the folder where your image is saved, choose the file, and click Insert.
