The latest phone cameras and some digital cameras have a facility to add GPS data to the Photos. Have you set GPS on your camera settings enabled on your Mobile/Camera ? if you share it on online websites like social media or emailed to some person, our location and other things can be tracked easily using these photos.
Now many websites remove the geo location tags from the photos you are uploading to the sites, but make sure you either disable this on the settings of will remove geo tags from the photos using some software's before you upload or email to someone.
This video from NBCA shows how serious is this. Watch this video