More info in here:
http://arvutiturve.wordpress.com/2011/03/23/fotode-korrastamine-sorteerimine-kuupaeva-ja-aasta-jargi-amok-exif-sorter/
AmoK Exif Sorter is the easy but powerful solution for renaming your photos. All pictures of a digital camera can be renamed by AmoK Exif Sorter based on the pictures' metadata (EXIF and IPTC). Meta data are stored in every picture automatically by the camera. The data include information about the date when the picture was taken (year, month, day, hour, second) but also information about camera model, aperture, exposure, picture's size, and many more.