iPhone Photos stuck in Landscape

Easy, and this was the only way to fix stuck orientation--

Simply Restart iPhone:

1. Press and hold the Sleep/Wake button until the red slider appears.
2. Drag the slider to turn your device completely off.
3. After the device turns off, press and hold the Sleep/Wake button again until you see the Apple logo.

Source: Restart your iPhone, iPad, or iPod touch - Apple Support