Specifications

The only tricky thing here is selecting the “Edit Header List...” from the list of
conditions and then entering “Content-Type” in the next window. “Content-Type”
will now appear in the list of conditions. You will need to select it and enter as its
content “multipart/related” or as “multipart/alternative.”
You might choose to replace the “Not in my previous recipients list” condition
with “Not in my Address Book” depending on your own correspondence patterns.
Adjust to suit your own tastes.
There is a small downside. It seems likely that this rule will move some “false posi-
tives” into the Junk folder. But checking that from time to time is much better than
wading through the image spam that Mail app’s Junk fi lter is currently missing.
Always check the messages in your Trash and Junk before deleting them.
To see all of the invisible information in the header of your email messages, go to
the View menu and scroll down to Message -> Show Long Headers. This works
when any email message is open.