Detecting if attachement is embedded or not

I've seen lots of discussion on this but no answers.

I have an addin (VB.NET and VSTO) that strips attachements from emails as
they are sent. Trouble is, I don't want to strip attachement (usually
images) that are within the body of the message. I quite often paste images
from the clipboard into my HTML messages and these need to be retained.

So when looping through the attachments in a message how can you robustly
check if the attachment is embedded or not?

Based on other articles I've...

Detecting if attachement is embedded or not