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Base64 Image to Teams

I was able to get this work in email perfectly, but I can't when posting to Teams. I have an output using HTML and the image coded in Base64 which does not seem to work in a Teams post. Everything else in the HTML does such as tables and formating. Is Base64 not supported in Teams maybe?

Community Support
Community Support

Hi @Anonymous ,


You can post table to Teams but posting an image to Microsoft Teams is not supported in Microsoft flow currently.



I afraid that there is no way to achieve your needs in Microsoft Flow currently.


If you would like this feature to be added in Microsoft Flow, please submit an idea to Flow Ideas Forum:


Best regards,



Community Support Team _ Mabel Mao
If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.

Thought I would post my workaround for this. I created HTML with Base64 using an email and sent it to Teams. Worked great.

Continued Contributor
Continued Contributor

Hi @Anonymous ,


I would suggest you to create a file from Base64 and store it Blob and get its URL . Use this URL in your message in teams like as following : 






(Please mark it resolved if it helps you)

Super User
Super User

If you use Base64 directly in the Post message action the flow would not complain but in Teams you will have a broken image.


The below will not work.





Use an image URL instead of Base64:




If you want use Base64 no matter what then you post an Adaptive card.




Sample below:


"type": "AdaptiveCard",
"body": [
"type": "Image",
"style": "Person",
"size": "Small"
"$schema": "",
"version": "1.0"









I did a copy-paste of what you had and it is failing. Looks like a permissions issue to MS Graph? I have not worked with Adaptive cards yet, so I am really interested in what you are saying here.

I really like this idea, but I don't think I can use Azure Blob Storage. It would be an additional cost and I don't think I could get it approved.

Looks like my copy blocked access to MS Graph, so I will have to try some other testing. Hopefully, I can get this to work. Thanks again for the idea.

I got it working in another Tenant using the Adaptive card. Very cool!

I am glad it is working with adaptive card. As this reply has answered your question or solved your issue, please mark this question as answered. Answered questions helps users in the future who may have the same issue or question quickly find a resolution via search. If you liked my response, please consider giving it a thumbs up. CHEERS!

is there a limit for the size of the Image that is used in Adaptiv Cards? I'm using the Base64 in the Adaptive Card and with some Images I get the error message (285x254, 29,95KB) "HTTP request error: The content is not a valid JSON". 

The Flow itself works and the JSON seems correct since it works with another image (1,45KB, 96x96).

I think there is a limit, but it isn't because of the card. I think there is a limit when using Base64. Does it work in an email?

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