Solution for: #115: 1&1 doesn't generate thumbnails for Wordpress

Switch to PHP5

1
Tell the server to use PHP5 by adding

AddType x-mapp-php5 .php
AddHandler x-mapp-php5 .php

to your .htaccess.

(thanks to http://www.blogoperium.de/wordpress/nextgengallery-thumbnail-problem-php/)