I show you example of geotagging, it's basically add or write location on the image exif data.
let say i take a picture with my phone, with geotagging enabled

(mind you that it require GPRS to work with, in my case, i already connect phone with laptop via usb to aquire internet, so, free of charge lah.. hehe )

the exif data of the picture i took will have extra information as shown below.


Geotagging usually require you to go out (open air) as the building may block the phone-to-satellites connection.
the more satellites connected, the more accurate the gps location will be.

i say indoor geotagging cos i do it inside my room.. huhuhu.. onli got 1 satellite connected. so, not accurate lah.. maybe 20 meters range from actual location..