I had been using iFunbox, but now it's telling me the current version of iOS only lets you access those files if the app maker enables file sharing. WTF? Any ideas? Don't want to have to jailbreak my iPad just to have custom portraits.
Edit: I've also attempted the method where you zip your portraits, changing the file extension to .bg1portrait, email it to yourself, then open it on your iPad using BG:EE. It kicks up BG:EE as expected, but then no additional portraits are available. Just the few I already added with iFunbox back in the day.