You can upload all your pics from your phone to facebook with a couple of clicks from the Android Gallery app. A lock in would be if you were not allowed to, or at least if they went out of their way to make that harder for you. But instead they go out of their way to put the share button and inter-app communication (intents) to allow you to easily share your pics with third parties.

I understand your frustration, and I too would like some kind of API to let us better control auto-upload. But "lock in" seems a bit of a stretch. You're asking to go out of their way, again, to better support competitors. When there's already a lot of support for them in place.