The method (an image is either attached or inserted) seems to me to be dependant on the email application.? Outlook always attaches files (unless you? go thru permutations,) while iOS always inserts them.? ?How they are received also seems to be unique.? iOS always leaves them inline,? ?Whiile Outlook seems to consistently leave them attached -- or duplicates w/ an attachment if one is inline.
KWKloeber