Outlook Signature With Logo Showing as Attachment: How to Fix Inline Display

Your Outlook email signature is appearing incorrectly, with the logo or image showing as a file attachment instead of being displayed within the signature itself. This makes your emails look unprofessional and can confuse recipients. The issue is typically caused by how the signature file is formatted or saved by Outlook. This article provides the steps to embed your logo correctly so it appears inline every time.

Why Outlook Shows Signature Images as Attachments

Outlook signatures are stored as HTML files. When you add an image, Outlook can either embed it directly into the HTML code or create a link to the image file on your computer or network. If the image is linked from a local file path, Outlook may treat it as an attachment when the original file cannot be found or accessed by the email client. This often happens after moving or deleting the original image file, or when the signature was created by copying and pasting from another document like Word or a webpage.

Another common cause is using the wrong method to insert the picture. Dragging and dropping an image file into the signature editor or using the clipboard to paste an image can sometimes create a temporary link instead of a permanent embed. The web version of Outlook and older desktop versions also handle image embedding differently, which can lead to inconsistencies.

Steps to Recreate Your Signature with an Inline Logo

The most reliable fix is to rebuild your signature from scratch using the correct procedure. This ensures the image data is stored directly within the signature file.

1. Open the Signatures and Stationery dialog
   In Outlook, go to File > Options > Mail. In the Compose messages section, click the Signatures button. This opens the main signature management window.
2. Delete the problematic signature
   In the Signatures and Stationery dialog, select the signature name that has the attachment issue from the list. Click the Delete button to remove it. Confirm the deletion if prompted.
3. Create a new signature
   Click the New button. In the pop-up window, type a name for your new signature, such as “Primary Signature with Logo,” and click OK. The new signature name will appear in the list.
4. Insert your logo using the Pictures tool
   With your new signature selected in the list, click in the large editing pane below. Type any text for your signature first. Then, place your cursor where you want the logo. Click the Insert Picture icon in the toolbar, which looks like a mountain landscape. In the menu, select Pictures > This Device. Navigate to and select your logo image file on your computer.
5. Format and assign the signature
   Use the formatting toolbar above the editing pane to adjust the logo size or add spacing. Below the editing pane, choose which email account this signature is for using the E-mail account dropdown. Then, set the signature for new messages and for replies/forwards using the respective dropdowns. Click OK to save and close all windows.

Alternative Method: Using a Base64 Encoded Image

For advanced control, you can encode your image directly into the HTML signature. This method is complex but guarantees the image travels with the email as text, never as a separate file.

1. Convert your image to Base64
   Use an online tool to convert your logo image file into a Base64 data string. Search for “image to base64 converter” in your browser.
2. Edit the signature HTML directly
   In the Signatures and Stationery dialog, after creating a new signature, click inside the editing pane. Use the formatting toolbar to add a small piece of text, like “X”. Select that text and click the Insert Hyperlink icon, then cancel to exit. This enables HTML editing. Right-click the signature editing pane and select View Source. Replace the existing code with an HTML img tag using the base64 string: <img src=”data:image/png;base64,YOUR_BASE64_CODE_HERE”>.
3. Save and test the signature
   Click OK in the HTML Source editor, then OK in the main signature dialog. Create a new email to test if the logo appears inline.

If Your Logo Still Appears as an Attachment

Outlook Web App Shows Logo as Attachment but Desktop Does Not

This discrepancy usually means the image is too large. Outlook Web App has stricter size limits for inline images. Reduce the physical dimensions and file size of your logo before reinserting it into the signature. Aim for a logo under 50 KB in file size.

Signature Works for New Emails but Not for Replies

You likely assigned the signature only for new messages. Go back to File > Options > Mail > Signatures. Select your signature, and in the Choose default signature section, ensure the same signature is selected in the dropdown for Replies/forwards.

Logo Disappears or Shows a Red X After Sending

A red X indicates a broken link. The signature is referencing an image file on a network drive or a location that the recipient’s email client cannot access. You must embed the image using the primary method described above, not link to it. Recreate the signature and use the Insert > Pictures > This Device method.

Signature Image Formats: Embedded vs Linked

Item	Embedded Image (Correct)	Linked Image (Causes Attachment)
Storage Location	Image data is stored within the signature HTML file	Signature contains only a file path or web URL to the image
Portability	Travels with the email, works offline	Requires the original file to remain in the exact same location
Recipient View	Logo displays inline consistently for all recipients	May show as attachment, broken icon, or not display at all
File Size Impact	Increases the size of the signature file itself	Keeps signature file small but risks display failure
Creation Method	Using Insert > Pictures within the Outlook signature editor	Copy-pasting from Word or dragging a file from desktop

You can now create professional email signatures with logos that display correctly within the message body. Test your new signature by sending an email to yourself and checking the Sent Items folder. For more advanced formatting, explore using tables within your signature to align text and images precisely.