Embed attached image in email body html via CID

Hello.

Is it possible to embed an attached image to email body html via the <img> tag with src = "cid:<some content id>"?

My current solution is:

1) Get ActivityMimeAttachments with "image/..." mime type related to the email
2) Get the ContentId property of these attachments
3) Add corresponding <img> tags to email description:

<img src="cid:<contentid value here>" alt = "Some image"/>

After that I save this email and send it via CRM Email router.
Recieved emails contain correct attachments and <img> tags with CIDs, but images aren't displayed in all browsers and email clients. Just empty squares with alt text.

I've googled a solution and found the following KB article: https://support.microsoft.com/ru-ru/kb/2934043. Maybe, this is the source of my problem?

Thanks.