Do you ever have a problem emailing receipts? I've encountered the same problem several times -- while the .jpg itself is completely fine on my end, the attachment does NOT go through okay.
I send it as window-friendly, and click control/c to turn it into an icon. When it's unsuccessful, and I go back in to check by clicking the icon in my sent mail, sure enough, it's not legible there, either.
I'm obviously doing something wrong, but I can't figure out what it is! It might have to do with the way I'm scanning it, but the issue seems to only be with email, not uploads.