We've come a long way, but we could take the experience even further. Let's talk about the current limitations of the app and some of the more complicated offline improvements that we've deferred until now.
Right now, the app can only resolve conflicts for the description of each to-do item. To do the same for maps and images, you'll need to implement a custom conflict resolution UI for each of these data types. This boils down to diff algorithms. You need a clear and efficient way to show the difference between an arbitrary number of different items. For text, this is relatively easy. For images and other binary data types, this is harder but not impossible. Search the Internet for image comparison algorithms if you're interested in learning more.