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 Riga.JPG
Creation Date2012-08-15 19:25:30
File Size168,354 bytes (164.4 KB)
Dimensions1024 x 768 pixels
GPS Coordinates 56.93383, 24.13933