An email signature image showing as attachment means the receiving app treats the picture as a separate file rather than as part of the message body. That depends on how the picture was packed into the message, and on the message format. The causes below come from Microsoft’s Outlook signature page, Microsoft’s page on message formats, Google’s Gmail signature page and the email standards RFC 2183 and RFC 2392, read in October 2026. No vendor publishes a list of which apps show a paperclip, so where we cannot cite one, we say so.
Email signature image showing as attachment: where to look
- Outlook: a signature built with VML tags can make elements appear as attachments (Microsoft).
- Message format: plain text cannot show pictures in the message, and Rich Text shows attachments as icons.
- How you added it: insert with the app’s own image button, not a paste from elsewhere.
- Hosting: a linked picture is not an attachment, but remote pictures may be blocked.
- Admin rules: a footer rule that fails to insert can wrap the whole original message as an attachment.
How a signature picture can travel
A picture reaches the reader in one of three ways. The way it travels decides whether you get an email signature image showing as attachment, or a clean inline logo.
| Method | How it travels | What the reader sees | Trade-off |
|---|---|---|---|
| Embedded in the message | Sent as a separate part of the same message, referred to from the HTML by a content ID | Shown in place, if the app treats it as inline | Makes each message bigger |
| Linked from a web address | Only an address is in the message; the app fetches the file | Shown in place, if remote pictures are allowed | May be blocked until the reader agrees |
| Attached as a file | Sent as an attachment | Listed as a file, perhaps with a paperclip | Clutters the message |
The standards behind the first and third rows are worth a short look.
- RFC 2392, which defines the
cid:link, says it refers to a specific body part of a message, generally one in the same message. An image tag in the HTML points at the picture part by its content ID. - RFC 2183 defines two dispositions. A part marked inline is meant to be shown automatically when the message is displayed. A part marked attachment is meant to be separate from the main body, with display depending on a further action by the user.
So the difference between a clean embedded logo and an email signature image showing as attachment can come down to a label on one part of the message, set by the sending app. Receiving apps then choose how to show it. We have not found a vendor page that spells out each app’s rule, so treat any claim that one app always shows a paperclip with care.
Causes of an email signature image showing as attachment, by symptom
| Symptom | Likely cause | Fix |
|---|---|---|
| Logo appears as a separate file in Outlook | A signature built with VML tags | Reinsert it with Outlook’s own Image button |
| Picture is missing from the body, listed as a file | The message was composed in plain text | Switch the message to HTML |
| Icons appear in the body instead of pictures | Rich Text Format in classic Outlook | Use HTML, the default |
| Every message shows a paperclip | A possible cause: the picture is embedded and the reader’s app lists it as a file | Host the picture and link to it |
| Whole original message arrives as a file | An admin disclaimer rule used the Wrap fallback | Ask the admin to review the fallback |
| Image only appears after clicking | The reader’s app blocks remote pictures | Not an attachment; see the hosting section |
The Outlook VML cause
The best-documented reason for an email signature image showing as attachment in Outlook is this one. Microsoft’s signature page says that using Vector Markup Language (VML) tags in a signature can cause some elements to appear as attachments instead of inline images. Its recommendation is to follow its own image steps: in classic Outlook, open Signature, then Signatures, pick the signature, select the Image button, locate the file and select Insert. Microsoft’s page does not say where the VML comes from. A signature pasted in from another tool is one possible route, which is why reinserting the picture by hand is the test. The Outlook picture guide goes further.
The message format cause
When the email signature image showing as attachment happens only on some messages, suspect the format. Microsoft’s format page is clear on this. HTML, the default in new and classic Outlook, allows embedded pictures. Plain text cannot show pictures in the message, and the pictures are attachments only. Rich Text Format, which is classic Outlook only and marked as legacy, shows attachments as icons within the message body. If your signature picture turns into an icon or file only on some messages, check the format of those messages first. In new Outlook, a single message changes through Options, then Switch to plain text. In classic Outlook, use the Format Text tab.
The admin rule cause
A mail flow rule that adds a disclaimer needs a fallback for messages it cannot modify, such as an encrypted one. Microsoft’s Exchange page says the default fallback, Wrap, creates a new message and attaches the original to it. That can look like an attachment problem. It is not your signature picture, but the fix is in the admin’s hands.
Stop an email signature image showing as attachment: fixes by app
| App | What to do | More |
|---|---|---|
| Classic Outlook | Delete the old picture, reinsert with the Image button, resize with the aspect ratio locked, keep the message in HTML | Classic Outlook guide |
| Gmail | Google offers three sources: Web Address (URL), My Drive or upload. A web address is a link rather than a file | Gmail image guide |
| Apple Mail on a Mac | Apple says you can drag an image into the signature editing column | Apple Mail guide |
| Any app | Try the other way of adding the picture and send a test | Logo guide |
On Gmail, Google’s troubleshooting page adds two conditions for a Drive picture: its sharing must allow anyone with the link to view it, and if the Drive file is deleted the picture stops showing.
Linking the picture to avoid an email signature image showing as attachment
Hosting the logo on your own site and linking to it keeps the picture out of the message entirely. The message carries only an address. Two catches apply.
- Remote pictures can be blocked. Microsoft’s page on automatic picture downloads in classic Outlook says Outlook blocks them by default and shows a bar offering Download Pictures. Google’s images help says Gmail shows them by default but not for senders it considers suspicious. Proton’s signature page says recipients need remote content on to see images in a signature.
- The file must stay put. If you rename or delete it, every old message loses the logo.
Give the picture alt text with the company name, and keep your name and number as real text. For teams, emailfooter has an optional (Beta) public files address for logos on your own WordPress site, with a hosting test first. That is a product feature, not a requirement of any app.
A signature that does not depend on the picture
If the logo is nice but not essential, design around it. A text signature with the logo as a bonus never looks broken. emailfooter draws this one, with made-up details:
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The name and contact lines are text, so the signature reads even if the logo does not load. The studio and person are made up.
Test before you roll it out
- Send a test message to a second provider, such as a free webmail account, and to your own address.
- Look for the paperclip or a listed file.
- Try again with remote pictures blocked, if the reader’s app lets you.
- Reply to your own message, then forward it, and look again. If the picture still looks wrong, return to the general diagnosis.
For a team signature, an email signature image showing as attachment for one person but not another often means they built it differently. emailfooter gives everyone the same layout and numbered steps for their app, but it does not write to mailboxes, so each person pastes and tests their own copy. It is English-only for now.
Frequently asked questions
Why is my email signature image showing as attachment?
In Outlook, Microsoft says VML tags in a signature can make elements appear as attachments instead of inline images. Plain text and Rich Text messages can also change how pictures show.
How do I stop my signature logo showing as an attachment?
Reinsert it with the app’s own image button, keep the message in HTML, or host the logo and link to it.
What is the paperclip on my signature email?
It marks a message that has an attached file. A picture sent as a separate attachment part can trigger it, which is why embedding and linking behave differently.
Does linking the image avoid attachments?
Yes, because only an address is in the message. The catch is that the reader’s app may block remote pictures until they allow them.
Keep reading
- Outlook signature images not displaying: blocked, blank and broken logos explained: Outlook signature images not displaying? Match what the reader sees to the cause, from blocked pictures to plain text, with fixes from Microsoft’s pages.
- How to add an image or logo to your Gmail signature: Add image to Gmail signature three ways (web address, Google Drive, upload), with Google’s size limits, the sharing setting that makes it show, and fixes.
- How to add a logo to your email signature in any email app: How to add logo to email signature in Gmail, Outlook and Apple Mail from one prepared file, with the format, pixel size, hosting choice and fixes.
- Email signature not showing: a symptom-first diagnosis for any mail app: Email signature not showing in any app? Match your symptom to the cause in one table, then follow a nine-question diagnosis flow with links to exact fixes.
Make every signature in your company match
emailfooter is a free WordPress plugin. You design the signature once, and each person adds their own details and installs it in their mail app. Prefer not to run a website? emailfooter Managed is the same software, hosted for you.