I have an email message that contains an embedded image.
The image in the email has a Content-ID and this content ID is referred in the body's html so this should come under the "related data" category, Chilkat handles it as an "attachment".
Why is this the case?
A "related item" is an image or other MIME sub-part that is contained within the multipart/related enclosure. I've had a look at the .eml you sent to me in private email, and it has the following MIME structure:
multipart/mixed multipart/alternative text/plain text/html image/png
The image is contained in the multipart/mixed enclosure (which is the typical place where attachments are located), and there is no multipart/related enclosure.
For example, a typical email that contains a multipart/related image referenced from HTML, and also has an attachment, would look like this:
multipart/mixed multipart/alternative text/plain multipart/related text/html image/jpeg application/pdf
PS> It's not feasible for Chilkat to be trying to parse the HTML body to determine if a particular image is "related" or not. The decision is based on the location of the image within the MIME structure.
Here's another example of an email with incorrect structure, where the HTML images are not properly placed inside a multipart/related enclosure, and are instead located where attachments should be..
multipart/mixed multipart/alternative text/plain text/html application/postscript application/pdf application/postscript application/x-zip-compressed application/octet-stream image/jpeg image/jpeg image/png image/jpeg image/png