I am using different image sizes in my templates which is very easy to install and configuring by adding
to the functions.php
Unfortunatle ngg only offers the original image size (or resized one at upload) and the thumbnail-size. the wp media code for the additional image sizes (as defined in the functions.php) has no effect to ngg. is there a plungin, hack or a trick for ngg to use the wp media settings (means: creating the image-derivates, assigning images also to the wp media gallery (alias), also getting the get_the_post_thumbnail(...) work with these image derivates? before you might ask, why i am using the ngg and not only the wp media: because the ngg is a perfect solution for image slideshows and image galleries. ngg is much easier because i can group images... the wp media gallery cannot group images, etc.