Photograph files taken with a digital camera also carry certain Exchangeable Image File Format (EXIF) data where you can see the camera settings that were set when the photo was taken.
If you want to make a clean install of the new OS X Mavericks or even the older versions of Mac OS X, than I strongly suggest you to create a bootable OS X key or a drive.
You probably heard about the alleged end of the world that could occur on December 21 2012 and about Mayan calendar predicting the apocalyptic events. Where did all this come from?