Originally Posted by nickdalzell
a factory reset won't touch your SD card. i had to do one on my phone because it just up and died and rebooted itself into a boot loop. all a factory reset does is format your /data partition so all your apps and home screen settings go bye bye.
He's using an HTC One, so no SD card. In my experience, a factory reset deletes everything on the on board storage. Just back up the photos to a PC