I didn't send it to myself, but that was a good suggestion.
However, I sent some pics this afternoon to my daughter, and she didn't receive them but the email is in my "sent" folder, and no messages came back saying it didn't go.
On some of the past ones that weren't received, the mailer demon (or whatever) sends a message back with something about MIME in the body of the message. Sorry to say I didn't keep them.
Earlier today a friend wrote to say that an email I forwarded to him with an attachment was received by him about 89 times, but he couldn't open any of them.
Sumptin spooky goin' on here.