Thanks alot for your fast reply!
I can confirm this way of embedding image by using base64 string works when sending the email to recipients using Outlook.
Unfortunately, opening the same email from Gmail web client resulted in failure. The base64 string is not converted to image, but is pasted directly in the body of the message.
I’m afraid this would not be a proper solution for the problem of sending the email to customers who might or might not be using Outlook.
Again, I thank you for suggesting the approach, it would work wonderfully if I would be sending internal company emails, but it’s not the solution to my problem.
Maybe anyone has another idea?