Our colleague, the wonderfully talented architectural photographer Connie Zhou, came up with a great method of getting around an iPhone or iPad’s desire to marry itself to a single copy of iTunes for the purpose of syncing photos.
If you don’t know what I’m talking about: after you’ve synced some photo albums to an iPhone with iTunes, if you then attach that phone to another computer and try to sync some albums, it will want to delete all the albums off your iPhone loaded by the previous copy of iTunes. Super annoying.
What Connie figured out is that if you tell iTunes to sync from a folder, rather than from iPhoto (it’s in the pop-up menu on the Photos tab in iTunes), the iPhone will get married to that folder, not that individual computer or copy of iTunes, and you can arbitrarily select any folders within it to be loaded (or unloaded) from the iPhone.
So, if that folder is on an external drive that you have with you, you can plug it into whatever computer is nearby, and sync it to your iPhone without iTunes threatening to delete things. Slick.
You could probably have the folder available over the internet too, by putting it on an externally accessible file server. Then you could just connect to the file server wherever you are, and sync away. Your server would probably need a decent upstream internet connection to make this work. (Note: We haven’t actually tried this.)