Missing image in email signature

Hi Jason,

This is a known pain point with Outlook Web / new Outlook: images embedded inline in a signature (base64 data or local attachments) often get stripped or stop rendering once the signature is saved and reused, especially across different Outlook clients (desktop, web, mobile) and when a recipient's client blocks embedded content by default.

The fix that has worked consistently for me: host the logo/image at a permanent, publicly-accessible HTTPS URL (not a local file or an embedded attachment) and reference it with a standard img src="https://..." tag. That way every client just fetches the image from the web instead of depending on how each app handles embedded content. Worth checking the raw HTML your signature editor generates - if it's using base64 image data or a cid: reference instead of a real https:// URL, that is almost always the root cause.

If it helps, I built a free checker at signatureforever.com/en/check - you paste your signature HTML and it flags exactly this kind of issue (embedded vs. hosted images) plus other things that break across Outlook desktop/web, Gmail and Apple Mail. Full disclosure, it is my own tool, but the check itself is free and needs no signup.

Hope that gets the image showing consistently for you.

Yes I created the signature in Outlook(PWA) and inserted an image tried both jpeg & png format for the image but both showed in the setup/edit section where I created the signature but neither showed the image when I tried to new new email or reply to a email, omly the text showed

Also noticed that when I reply to a customers email where they have a logo image if removes it from signature and attaches it as an image

Dear @Jason Boardman,

Thank you for your update,

This behavior is typically related to how Outlook on the web handles images in signatures. Unlike Classic Outlook, Outlook Web does not fully support embedded or locally stored images in signatures, and it may convert or strip them during message composition or reply. To resolve or work around this issue, you can try: Hosting the image externally (e.g., SharePoint or a public URL) and inserting it via a direct image link instead of pasting it. And if you cannot insert it via link, try to copy the image then paste in direct into add signature setting. Testing in a different browser or using InPrivate mode to rule out caching or browser-related issues. When replying to emails, Outlook may not preserve inline images in the original signature and instead converts them into attachments. This is expected behavior due to how Outlook processes message formatting and embedded images during replies, especially in Outlook on the web.

In the meantime, try to use New Outlook desktop app to check the image appear or not.

If the issue still persists, I recommend you contact to Microsoft Support team. The Microsoft Online Support Team has higher permission than us moderators to remotely assist you and collect background logs for the root cause. This is a more efficient and direct way in recovering this scenario for you.

If you are user, you can contact to your IT/administrator and they can follow steps in this link Get support - Microsoft 365 admin. 

And if you are global admin of your organization, you can use this link to find the appropriate contact number: Global Customer Service phone numbers - Microsoft Support  

Note: Please understand that as forum moderator, my primary goal is to provide helpful guidance and support through general troubleshooting steps. While I don’t have access to internal systems or test devices required to resolve backend issues, I truly appreciate your understanding of these limitations. I genuinely hope the information I share helps guide you in the right direction, and I'm always here to assist as much as I can within my scope.   

Dear @Jason Boardman,

Thank you for posting your question in the Microsoft Q&A forum.

Please understand that our forum is a public platform, and we will modify your question to cover your organization domain name in the description. Please notice to hide these personal or organization information next time you post error or some information to protect personal data.

Based on your description, you set up an email signature with a logo in Outlook, but when composing or replying to emails, only the text appears while the image is missing.

I have tested inserting an image into a signature, and it worked correctly in my test environment.

Could you please share how you created the signature on your side so I can better understand your situation?

In the meantime, to insert an image into a signature, you can follow the steps below:

Log in your business account in Outlook

Click New message > in the pane menu > Insert tab > Signature > add your signature, then you can insert your image in your signature.

Please let me know if it works on your side. If you encounter any issues or get stuck at any step, feel free to let me know so I can support you more effectively.

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