Just curious, do either of the attachment options in Apple Mail (e.g., "Always Send Windows-Friendly Attachments" or "Always Insert Attachments at End of Message") have any effect on Mail -> Outlook compatibility?
(If I recall from my research many years ago, they don't help, but I don't have Outlook to test.)
The mail attachment options, sadly, have no influence on how the images get delivered. Tried that today to no avail