If you want to create 1 large jpg of thumbnails you could use picasa from google, it has the ability to create such a thing from a folder of pictures.
At the moment the HTML templates can only have 1 picture per row so without some complicated coding pictures side-by-side at the moment are not possible.
Maybe this may interest someone to create some code that will do that as it would be handy to save paper when printing the html templates as they are.
Cheers