Flowable Email Task sending image attachment

Hi,
I want to send email to outlook users with showing some background image. But outlook only supports embedded attachment with data link like

I have success sent image attachment as encoded base64 string via flowable email task.
But I found there is no way in flowable attachment to set the content id of base64 string.
is there any way I can set the content id? so that my image able to like it success?

My environment:
Springboot 2.7 + Flowable 6.7.2

currently my email sending with attachment looks as below:

------=_Part_0_374660691.1662369258777
Content-Type: image/png; name=email_logo.png
Content-Transfer-Encoding: base64
Content-Disposition: attachment; filename=email_logo.png