If you're in the client and you click;
File, Import then type or paste an import file name;
for example: Mypicture.jpg and press Enter,
Notes will prompt you to Preserve Existing Line Breaks in Text?
It will then import gobbledy-gook.
If you want to import a JPEG, you either have to type the name and then choose JPEG in the Files of Type box or you have to click on a JPEG File.
This has been a problem for years and I keep thinking that someone will wise up and fix it but it's not happening.