Yer-Man's input was spot-on; I was totally overlooking the line below the "From" line. It appears when adding images but I didn't catch it. I just fired off another email to the magazine editor, and checked the image in the Sent emails folder. It was 1.8MB, the original as it sits on my desktop. Hopefully that will be enough for them... 67kb-84kb certainly wasn't.
Tony, I will go to the WD passport external drive holding most of my pix, and see if I can determine what its size is there. Being that it probably originated on my 5MP first digital camera with a 2GB CompactFlash card, the 1.8MB image could be original.
One issue I've not had time to attend to is that external hard drive. I moved all my pix and important documents to it long ago when the old Dell XP computer got too sluggish trying to carry it all. That worked until the Dell quit altogether, but for some reason I had formatted the external drive to NTFS. So when I plugged it into the new MacBook, it could read the things on the drive but not copy to it or directly transfer anything off of it. One day I discovered I could copy an image off the drive to the MacBook's desktop, and then drag or copy/paste or attach that one, or edit it. I just can't put the edit or anything else onto the drive until I convert it back to Fat32. At least that's how I understand it. Formatting used to drive me nuts when I got a Sony digital mini-disc movie camera decades ago; too many format options trying to make things jive with disc players. I never did figure that out and haven't used that otherwise great camera since 2007.
Thanks all for the input. Apple's Community is drastically better at answering questions than Microsoft's.