This program requires the PHP 'mysql' extension.
This program requires the PHP 'GD' extension.
Please ask your server administrator to install missing PHP extension(s).

PHP doesn't support jpegs (or thumbnails). Please ask your server administrator to recompile PHP with jpeg support.
Server Administrators: imagecreatefromjpeg() isn't defined. Search these comments on php.net for 'undefined function' for more details.