What is Geotagging?
“Geotagging (also written as GeoTagging) is the process of adding geographical identification metadata to various media such as a geotagged photograph or video, websites, SMS messages, QR Codes or RSS feeds and is a form of geospatial metadata. This data usually consists of latitude and longitude coordinates, though they can also include altitude, bearing, distance, accuracy data, and place names.”
So in a nutshell this mean if you using a modern device that uses GPS your latitude and longitude coordinates could be stored in the picture that is taken.
From a security point of view this means if you upload a picture to Twitter from your phone, it could be possible for someone to find the location where that picture was taken, this was used recently to track down an anonymous hacker who posted a picture of his girlfriend online the FBI used the images latitude and longitude coordinates to locate where the picture was taken and a few days later he was arrested.
It just goes to show you should be careful when using smart devices and uploading images.
In order to get the information from the image here a quick and dirty PHP script:
link to article
Geo tagging used to find hacker