Nowadays every photo taken with a mobile phone or digital camera contains metadata. This metadata, called Exif data, contains information about your camera, like brand and model name, the dimensions of the image and - when available - also GPS coordinates which reveal the location where the picture was taken.
File NameExample Teatro Scala.JPG
Creation Date2012-02-18 22:15:34
File Size266,358 bytes (260.1 KB)
Dimensions1024 x 768 pixels
GPS Coordinates 45.467, 9.18967