In my case it was "too big" to be attached to an email. Where does it go in iTunes I have no clue, for I've never used it for anything but music about 10 years ago. Sadly ability to save PSD to files wasn't added to the last upgrade of the original ArtStudio.
Ple-e-ese, I know working on the old AS is not a priority, plus it's not financially rewarding anymore, but there should be an easy way to transfer layered files into the Pro. The best would be to add the ability to read/convert old .art format.