We released a minor update (1.1.1) to the mobile Photosynth App last week (reason: iOS5 compatibility and new Facebook API compatibility), but responding to twitter reports from @itsShoBoy and @phillustrations, we've discovered a bug we inadvertently introduced:
If you change your settings, these new settings are not remembered across app restarts.
We have a fix for this, and will be submitting it to the App Store within a few days. You'll see a 1.1.2 version emerge after the App Store reviews it.
Until then, I'm afraid you'll need to adjust settings each time the App is restarted.
David Gedye and the Photosynth Team