In the NSP module, do you want one category to be shown? Or do you want to show more than one category?
If only one category is going to be shown, i.e. all the articles belong to the same category, then you can costumize the module in order to the thumbails aren't shown. Go to module options and deactivate the thumbnails.
If more than one category are shown in module, then you have to customize the modele in order to check the article category and show or not to show.
Into the template code you have a folder "html" with another modules that overwrite the code of the original modules. Take a look.