Requirements

•  A webserver with PHP 4.1.0 or greater (PHP 4.3.x recommended to get full functionnality)

I meet the requirements, take me to the download page.

Optional

•  convert utility from ImageMagick if your PHP configuration doesn’t support the use of GD (used for automatic thumbnail/lowres picture generation)
  
•  MySQL if you prefeer using it instead of the default fast text database
  
•  exiftran or jpegtran for the lossless jpeg rotation