Good point, and most likely not.

I'm not very familiar with the background process APIs, but from my understanding of it, I'd be surprised if you were able to do that. In my comment I was mostly thinking of automatic upload as the user uses the app itself: opens Dropbox to check out a document and it automatically gets the new pictures without the user having to remember to do it.

though not exactly "automatically" by the native camera app, but this app uploads directly to your db-account: http://itunes.apple.com/us/app/quickshot-with-dropbox/id4051... (and does it well!)