MacOS 10.15.6 Catalina
I have been importing data from Evernote as HTML from .enex files. I happened to take a look in the "joplin-desktop/resources" directory and found numerous corrupted (actually, truncated) .jpg files. There is nothing wrong with the .enex export, as I can re-import into Evernote and the graphics files are intact.
I currently have around 9,000 files in the "resources" directory, and just by browsing through them for a few minutes, it appears that somewhere between 50%-75% are truncated.
This is obviously a bit of a show-stopper as far as migrating to Joplin...