That's a nice discovery, Charlie!
Mike, tagging onto Charlie's idea...
UPDATE: the below idea doesn't work so don't waste time trying it out. See my post below that explains this more fully.If you use a program that will batch convert WAV to MP3, the MP3s will then load. One such program is Fre:Ac. It's free and it's available at the below URL.
https://www.freac.org/Regards,
Noel