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 Benidorm.JPG
Creation Date2011-03-26 14:37:44
File Size397,011 bytes (387.7 KB)
Dimensions1024 x 765 pixels
GPS Coordinates 38.53133, -0.16383