Changing the number of thumbnails in a row below a product image

Q: I’ve changed the dimensions of the product image in the Jigoshop settings but the thumbnails below do not reflect the large container.
On inspection, I can see that the images have a first and last class on the first and third image of each row.
How do I go about changing these so that I can fit 5 in a row?

A: You can put the following into your theme’s functions.php:

 add_filter(  'single_thumbnail_columns', 5 );

… where the ‘5’ is the number of thumbnail columns you want.